* Nature : "Telomerase reactivation reverses
tissue degeneration in aged telomerase-deficient mice "
Scientists say they have taken an intriguing first step in the
search for the fountain of youth. Scientists experimented with
mice that were the equivalent of 80-year-old humans and found
they were able to reverse the aging process.
Scientists in Boston have made an astounding discovery, taking
aging mice and turning them young again, like tiny little
Benjamin Buttons.
Just like the title character in the Hollywood film version of
"The Curious Case of Benjamin Button," the mice appeared to not
only stop aging but grow younger.
Molecular biologist Dr. Ronald DePinho at Harvard Medical School
in Boston was able to pull off the feat by playing with
"telomeres" -- the protective DNA caps on the ends of our
chromosomes.
The caps, which have long been implicated in aging, prevent our
chromosomes from "fraying" and the genes inside them from
"unravelling."
Scientists have long known that a little bit of our telomeres
erodes each time our cells divide. Previous research has shown
that people with longer telomeres tend to live longer, whereas
those with shorter telomeres suffer more from age-related
diseases, such as Alzheimer's.
A few years ago, DePinho and his research team devised a way to
engineer mice so that they lacked a working copy of the gene
that regulates the production of telomerase, which is an enzyme
that strengthens telomeres and whose production declines over
time.
Instead of dying at three years old, the genetically engineered
mice died at about six months. By the time they died, they had
become infertile, their coat hair had turned grey and they had
developed age-related conditions such as osteoporosis.
DePinho wondered whether he could reverse the aging in the mice
if they suddenly began making telomerase again.
So he took a group of engineered mice and added back the
telomerase gene, but left it inactive. His team then allowed the
mice to age for six months, until they were the equivalent of
80-year-old humans. They then gave the mice a drug that
"switched on" the telomerase gene.
One month later, not only did the new production of telomerase
stop the aging process in the mice, it appeared to actually undo
the premature aging so that the mice became the physiological
equivalent of young adults.
Even DePinho was surprised at how effective the experiment was.
"We expected to see a slowing or a stabilization of aging.
Instead, what we found was a dramatic reversal in aging," he
told CTV.
"The shrunken brains increased, new neurons were formed, the
coat hair was restored to a new sheen."
DePinho notes that the treated mice went on to have a normal
lifespan. They were simply healthier and biologically younger.
DePinto and his colleagues stress that the study was a
"proof-of-concept" experiment, designed to show that changes to
telomerase can affect aging. There are still many questions to
answer before an experiment can be tried on humans.
For example, some research has shown that telomerase seems to
help cancer tumours grow faster. DePinho says his team didn't
observe any cancers in the mice, but then the telomerase was
activated for only one month.
"This teaches us something fundamental about aging: that aged
tissue -- even very aged tissue -- retains the ability to
rejuvenate itself," he said.
DePinho says it's possible the method could be used to treat
people with rare genetic premature aging syndromes. Whether the
technique could help reverse normal aging still remains to be
seen. Still, he says the findings were worth sharing and appear
in the journal Nature.
"The results were so dramatic that we wanted to get them out to
the research community as soon as possible so we could inspire
the research community to move forward on these findings,"
DePinho said.
PATENTS
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US
6767719
Protein and peptide
fragments from mouse telomerase reverse transcriptase
Inventor: MORIN GREGG B
[CA] ; ALLSOPP RICHARD
Abstract --- This invention
provides for murine telomerase reverse transcriptase (mTERT)
enzyme proteins and nucleic acids, including methods for
isolating and expressing these nucleic acids and proteins,
which have application to the control of cell proliferation
and aging, including the control of age-related diseases, such
as cancer.
Description
[0002] This application is a continuation-in-part of and claims
the priority benefit of U.S. patent application Ser. No.
08/979,742, filed Nov. 26, 1997, now abandoned.
[0003] Incorporated herein by reference in their entirety and
for all purposes are the following: U.S. patent application Ser.
Nos. 08/979,742; 08/974,549; and 08/974,584; PCT Applications
PCT/US97/17618 and PCT/US97/17885; and U.S. patent application
Ser. Nos. 08/915,503, 08/912,951, 08/911,312, 08/854,050,
08/851,843, 08/846,017, 08/844,419, and 08/724,643.
[0004] This invention was made with United States Government
support under Grant No. HD/CA 34880, awarded by the National
Institutes of Health. The United States Government has certain
rights in the invention.
FIELD OF THE INVENTION
[0005] The subject matter of this application provides novel
recombinant telomerase enzyme genes and proteins and relates to
the cloning and characterization of the catalytic protein
component of mouse telomerase enzyme, referred to as mouse
telomerase reverse transcriptase ("mTERT").
[0006] This invention pertains generally to cell proliferation
and aging, including the fields of age-related diseases, such as
cancer and cell biology. In particular, this invention pertains
to the discovery of a novel mTERT enzyme proteins and nucleic
acids, and methods for isolating and expressing by recombinant
means these nucleic acids and proteins. The invention provides
antibodies specifically reactive with mTERT. The invention also
pertains to methods of screening for novel mTERT activity
modulators. The invention also includes means of mortalizing
cells, creating indefinitely proliferating cells and
immortalizing cells, including normal, diploid cells, using the
novel reagents, proteins, nucleic acids, enzymes and methods of
the invention.
BACKGROUND OF THE INVENTION
[0007] The following discussion is intended to provide general
information regarding the field of the present invention. The
citation of various references is not to be construed as an
admission of prior invention.
[0008] Telomeres, the protein-DNA structures physically located
on the ends of chromosomes in eukaryotic organisms, are required
for chromosome stability and are involved in chromosomal
organization within the nucleus (Zakian (1995) Science 270:1601,
Blackburn (1978) J. Mol. Biol., 120:33, Oka (1980) Gene 10:301,
Klobutcher (1981) Proc. Natl. Acad. Sci. USA 78:3015). Telomeres
are believed to be essential in most eukaryotes, as they allow
cells to distinguish intact from broken chromosomes, protect
chromosomes from degradation, and act as substrates for
replication. Telomere loss, i.e., inability to maintain telomere
structure, is associated with normal human cellular development,
including cell aging and cellular senescence. Telomere gain,
i.e., the ability to maintain telomere structure in cells, is
associated with chromosomal changes and cancer.
[0009] Telomeres are generally replicated in a complex, cell
cycle and developmentally regulated manner by a
"ribonucleoprotein telomerase enzyme complex." The telomerase
reverse transcriptase enzyme is a telomere-specific
RNA-dependent DNA polymerase comprising a telomerase reverse
transcriptase (TERT) protein and an RNA component. Telomerase
enzyme uses its RNA component to specify the addition of
telomeric DNA repeat sequences to chromosomal ends (U.S. Pat.
No. 5,583,016; Villeponteau (1996) Cell and Develop. Biol.
7:15-21). In addition to the template RNA component, other
proteins have been found to be associated with TRT. For example,
telomerase-associated proteins called p80 and p95 were found in
Tetrahymena (Collins (1995) Cell 81:677). Homologs of the p80
protein have been found in humans, rats and mice. Neither
enzymatic activity nor amino acid motifs typically associated
with RNA-dependent DNA polymerases have been found to be
associated with these proteins (Harrington (1997) Science
275:973-977). In contrast, mutational analysis and
reconstitution in vitro have shown the TERT proteins contain the
catalytic moieties of telomerase (Lingner (1997) Science
276:561-567; Weinrich (1997) Nature Genetics 17:498-502).
Various structural proteins that interact with telomeric DNA
that are distinct from the protein components of TRT have also
been described. In mammals, most of the simple repeated
telomeric DNA is packaged in closely spaced nucleosomes (Makarov
(1993) Cell 73:775, Tommerup (1994) Mol. Cell. Biol. 14:5777).
However, the telomeric repeats located at the very ends of the
human chromosomes appear to be in a non-nucleosomal structure
that has been termed the telosome.
[0010] Telomeric DNA can consist of a variety of different
structures. Typically, telomeres are tandem arrays of very
simple sequences, such as simple repetitive sequences rich in G
residues, in the strand that runs 5' to 3' toward the
chromosomal end. In humans, the telomere repeat sequence is
5'-TTAGGG-3' (SEQ ID NO:7). In contrast, telomeric DNA in
Tetrahymena is comprised of repeats of the sequence T2G4, while
in Oxytricha, the repeat sequence is T4G4 (Zakian (1995) Science
270:1601; Lingner (1994) Genes Develop. 8:1984). Heterogenous
telomeric sequences have been reported in some organisms, such
as the repeat sequence TG1-3 in Saccharomyces. The repeated
telomeric sequence in other organisms is much longer, such as
the 25 base pair repeat sequence of Kluyveromyces lactis.
Furthermore, telomeric structure can be completely different in
other organisms. For example, the telomeres of Drosophila are
comprised of a transposable element (Biessman (1990) Cell
61:663, Sheen (1994) Proc. Natl. Acad. Sci. USA 91:12510).
[0011] In most organisms, the size of the telomere fluctuates.
For example, the amount of telomeric DNA at individual yeast
telomeres in a wild-type strain may range from approximately 200
to 400 bp, with this amount of DNA increasing and decreasing
stochastically (Shampay (1988) Proc. Natl. Acad. Sci. USA
85:534). Heterogeneity and spontaneous changes in telomere
length may reflect a complex balance between the processes
involved in degradation and lengthening of telomeric tracts. In
addition, genetic, nutritional and other factors may cause
increases or decreases in telomeric length (Lustig (1986) Proc.
Natl. Acad. Sci. USA 83:1398, Sandell (1994) Cell 91:12061).
[0012] Telomeres are not maintained via conventional replicative
processes. Complete replication of the ends of linear eukaryotic
chromosomes presents special problems for conventional methods
of DNA replication. Conventional DNA polymerases cannot begin
DNA synthesis de novo; rather, they require RNA primers that are
later removed during replication. In the case of telomeres,
removal of the RNA primer from the lagging-strand end would
necessarily leave a 5'-terminal gap, resulting in the loss of
sequence from the leading strand if the daughter telomere was
subsequently blunt-ended (Watson, (1972) Nature New Biol.
239:197, Olovnikov (1973) J. Theor. Biol., 41:181).
[0013] While conventional DNA polymerases cannot accurately
reproduce chromosomal DNA ends, specialized factors exist to
ensure their complete replication. The telomerase enzyme is a
key component in this process. In vivo, telomerase enzyme is
assembled as a ribonucleoprotein (RNP) enzyme complex. It is an
RNA-dependent DNA polymerase that uses a portion of its internal
RNA moiety as a template for telomere repeat DNA synthesis (Yu
(1990) Nature 344:126; Singer (1994) Science 266:404; Autexier
(1994) Genes Develop. 8:563; Gilley (1995) Genes Develop.
9:2214; McEachern (1995) Nature 367:403; Blackburn (1992) Ann.
Rev. Biochem. 61:113; Greider (1996) Ann. Rev. Became. 65:337).
A combination of factors, including telomerase processivity,
frequency of action at individual telomeres, and the rate of
degradation of telomeric DNA, contribute to the size of the
telomeres (i.e., whether they are lengthened, shortened, or
maintained at a certain size). In vitro, telomerases may be
extremely processive; for example, Tetrahymena telomerase can
add an average of approximately 500 bases to the G strand primer
before dissociation of the enzyme (Greider (1991) Mol. Cell.
Biol., 11:4572).
[0014] Telomere replication is regulated both by developmental
and cell cycle factors. Telomere replication may play a
signaling role in the cell cycle. For example, certain DNA
structures or DNA-protein complex formations may act as a
checkpoint to indicate that chromosomal replication has been
completed (Wellinger (1993) Mol. Cell. Biol. 13:4057). Telomere
length is also believed to serve as a mitotic clock, which
serves to limit the replication potential of cells in vivo and
in vitro.
[0015] In humans, telomerase activity is not detectable in most
somatic tissues. Cell that express either no or only low amounts
of telomerase, such as somatic cells, undergo progressive
telomere shortening with increasing age (Harley (1990) Nature
345:458, Harley (1994) Cold Spring Harbor Symp. Quant. Biol.
59:307). Some non-transformed, non-immortal cells have
detectable telomerase activity. Germline cells express
telomerase as required to maintain telomeric structure of
chromosomes passed from generation to generation (Greider,
(1996) Annu. Rev. Became. 65:337). Low levels of telomerase
activity have been detected in activated human B and T
lymphocytes and hematopoietic progenitor cells (Keiko (1995) J.
Immunol. 155:3711; Igarshi (1997) Blood 89:1299-1307; Igarashi
(1996) Biochem. Biophys. Res. Commun. 219:649; Norrback (1996)
Blood 88:222).
[0016] Immortalized cells, such as most cancer cells, express
significantly higher levels of telomerase, allowing for
stabilization of telomeric structure. Telomerase activity has
been detected in about 85% of biopsies from more than 950
primary human tumors (Kim (1994) Science 266:2011; Hiyama (1995)
Nature Med. 1:249-257; Counter (1992) EMBO J. 11:192).
Telomerase activity has been detected in many cancers (Wellinger
(1993) supra; Autexier (1996) Trends Biochem. Sci. 21:387).
However, even in telomerase-positive cells, such as most cancer
cells, the levels of telomerase are very low relative to
housekeeping and structural proteins.
[0017] Because telomerase is expressed (albeit in low levels) in
most human cancer cells and is negligibly expressed in other
cell types, it is the only true pan-cancer cell marker
identified to date. Thus, there exists a great need for
inhibitors of telomerase activity, which would be ideal
therapeutic compositions in the treatment of cancer or
uncontrolled cell growth. Furthermore, loss of or inhibition of
telomerase activity is associated with cellular senescence and
may lead to cell death. Therefore, there exists a great need for
methods and compositions capable of promoting or reconstituting
telomerase activity which would be useful in treating
age-related disease and anti-aging pharmaceuticals. The present
invention fulfills these and other needs.
SUMMARY OF THE INVENTION
[0018] This invention has for the first time provided the
identification, cloning and characterization of mouse telomerase
reverse transcriptase (mTERT) proteins and nucleic acids. Mouse
telomerase enzymes, including associated nucleic acids and other
polypeptides, are further provided. Also, the invention provides
novel reagents and methods complementing this significant
achievement.
[0019] The invention provides for an isolated or recombinant
nucleic acid encoding an mTERT, the protein defined as having a
calculated molecular weight of between 50 and 150 kDa, and
specifically binding to an antibody raised against the protein
of SEQ ID NO:2, or a subsequence thereof, or having at least 60%
amino acid sequence identity to an mTERT protein comprising SEQ
ID NO:2. In one embodiment, the calculated molecular weight of
the encoded mTERT protein is about 127 kDa. In further
embodiments, the encoded protein has at least 80% amino acid
sequence identity to a protein comprising SEQ ID NO:2, or, the
encoded protein comprises SEQ ID NO:2.
[0020] In alternative embodiments, the invention provides for an
isolated or recombinant nucleic acid which specifically
hybridizes to SEQ ID NO:1 under stringent conditions, an
isolated nucleic acid encoding a protein which specifically
binds to an antibody directed against a protein comprising SEQ
ID NO:2, and an isolated nucleic acid comprising either 10 to 15
or more nucleotides identical or exactly complementary to SEQ ID
NO:1 or a nucleotide sequence encoding at least about five
contiguous amino acids of an mTERT, wherein the TERT has an
amino acid sequence as set forth in SEQ ID NO:2 or conservative
substitutions of said amino acid sequence. In another
embodiment, the invention provides an isolated nucleic acid
encoding a fusion protein comprising an mTERT. The invention
also provides a nucleic acid free of dideoxynucleotides, as well
as nucleic acids comprising non-naturally occurring nucleotides.
One embodiment provides for an isolated nucleic acid comprising
a label and a nucleotide sequence of the invention.
[0021] The invention also provides for an isolated or
recombinant peptide encoded by a recombinant or isolated
nucleotide sequence encoding at least about five contiguous
amino acids of an mTERT.
[0022] In another embodiment, the invention provides for an
isolated or recombinant mTERT protein where the mTERT has a
calculated molecular weight of about 50 to 150 kDa; and
specifically binds to an antibody raised against a protein
comprising SEQ ID NO:2, or subsequence thereof, or has 60% amino
acid sequence identity to a protein comprising SEQ ID NO:2. The
isolated or recombinant mTERT protein can have a calculated
molecular weight of about 127 kDa, or the protein can comprise
SEQ ID NO:2. In an alternative embodiments, the isolated or
recombinant mTERT protein is encoded by a nucleic acid molecule
which specifically hybridizes to SEQ ID NO:1; and, the isolated
or recombinant mTERT protein, or subsequence thereof, can
further comprise a fusion protein.
[0023] The invention provides for an isolated or recombinant
antibody specifically immunoreactive under immunologically
reactive conditions to an mTERT protein; the mTERT protein can
comprise the sequence as set forth in SEQ ID NO:2. The invention
also provides for an isolated or recombinant antibody,
specifically immunoreactive under immunologically reactive
conditions, to an mTERT protein encoded by the nucleic acid of
claim 1; the nucleic acid can comprise the sequence as set forth
in SEQ ID NO:1. The invention further provides for an isolated
or recombinant mTERT protein which specifically binds to the
anti-mTERT antibodies of the invention.
[0024] Alternative embodiments provide for a transfected cell
comprising a heterologous gene encoding a mTERT protein or
subsequence thereof; a transfected cell into which an exogenous
nucleic acid sequence has been introduced, where the nucleic
acid specifically hybridizes under stringent conditions to SEQ
ID NO:1 or a nucleic acid of the invention as described herein,
and the cell expresses the exogenous nucleic acid as an mTERT
protein; and a transfected cell where the transfected cell is a
karotypically normal diploid cell.
[0025] The invention also provides for an organism into which an
exogenous nucleic acid sequence has been introduced, the nucleic
acid specifically hybridizing under stringent conditions to a
nucleic acid with a sequence as set forth in SEQ ID NO:1, or a
nucleic acid of the invention as described herein, and the
organism expresses the exogenous nucleic acid as a mouse TERT
protein. The organism can express an exogenous nucleic acid
comprising a nucleic acid of the invention. Alternatively, the
organism expresses and translates an exogenous nucleic acid
sequence into a mouse TERT protein, which can be expressed
externally from the organism. The organism can be an insect, as
a Spodoptera sp., Trichoplusia sp. or a Lymantria sp. The insect
can specifically be a Spodoptera frugiperda, Trichoplusia ni or
a Lymantria dispar. The organism can be a plant, a fungus or a
yeast. If it is a yeast, the organism can be a Pichia sp.,
Hansenula sp., Torulopsis sp., Saccharomyces sp., or a Candida
sp. The yeast can specifically be a Pichia pastoris, Hansenula
polymorpha, Torulopsis holmil, Saccharomyces fragilis,
Saccharomyces cerevisiae, Saccharomyces lactis, or a Candida
pseudotropicalis. The organism can be a bacterium, such as
Escherichia coli, Streptococcus cremoris, Streptococcus lactis,
Streptococcus thermophilus, Leuconostoc citrovorum, Leuconostoc
mesenteroides, Lactobacillus acidophilus, Lactobacillus lactis,
Bifidobacterium bifidum, Bifidobacteriu breve, or a
Bifidobacterium longum.
[0026] The invention also provides for an expression vector
comprising a nucleic acid sequence which specifically hybridizes
under stringent conditions to an mTERT encoding nucleic acid;
the nucleic acid can have a sequence as set forth in SEQ ID
NO:1.
[0027] The invention also provides for a transfected cell
comprising a recombinant mTERT, wherein said cell is comprised
in a transgenic non-human animal. The invention also provides
for a transgenic animal which lacks a functional mTERT due to
its being "knocked out" using recombinant methods and reagents
of the invention. Such mTERT knockouts mice are especially
useful in studying the effect of telomerase and in testing
anti-cancer telomerase inhibitors, i.e., in mice comprising
human tumor xenografts.
[0028] In one embodiment, the invention provides for a
transgenic cell or non-human animal, and progeny thereof,
wherein said animal comprises an endogenous mTERT gene which has
been mutated by recombinant means with a nucleic acid comprising
a subsequence of a nucleic acid encoding an mTERT or
complementary to an mTERT. The transgenic cell or non-human
animal can be deficient in at least one mTERT or telomerase
enzyme activity, or completely lack all mTERT or telomerase
enzyme activity. The transgenic cell or non-human animal can
comprise an mTERT with a deficiency in activity which is a
result of a mutated gene encoding an mTERT having a reduced
level of a telomerase enzyme activity compared to a wild-type
telomerase enzyme activity. The transgenic cell or non-human
animal can contain a mutated mTERT gene comprising one or more
mutations selected from the group consisting of a missense
mutation, a substitution, a nonsense mutation, an insertion, or
a deletion. The transgenic cell or non-human animal can be a
mouse, i.e., of the family Muridae. In particular, M. spretus or
M. musculus spp. are provided. The transgenic non-human animal
can further comprise a human telomerase reverse transcriptase.
[0029] The invention further provides for a kit for the
detection of a mouse TERT gene or polypeptide, the kit
comprising a container containing a molecule which can be a TERT
nucleic acid or subsequence thereof, a TERT polypeptide or
subsequence thereof, or an anti-TERT antibody.
[0030] The invention also provides a method of determining
whether a test compound is a modulator of mTERT or telomerase
enzyme activity, the method comprising the steps of: providing a
mouse TERT composition, contacting the TERT with the test
compound and measuring the activity of the TERT, where a change
in TERT activity in the presence of the test compound is an
indicator of whether the test compound modulates mouse TERT or
telomerase enzyme activity.
[0031] In a further embodiment, the method is carried out in a
buffered aqueous solution comprising a template polynucleotide,
an mTERT, a buffered aqueous solution compatible with telomerase
enzyme activity, and sufficient additional nucleotide species
necessary for telomerase-catalyzed polymerization of a DNA
polynucleotide complementary to said template polynucleotide.
This method can be carried out in a cell-free extract, an
organism or a transgenic organism. In alternative embodiments of
this method: the DNA is a telomere or comprises a telomeric
sequence; the template polynucleotide is a mouse telomerase RNA
(mTR, or mouse telomerase related component, or mTERC) or
comprises an mTERC subsequence; the activity of the telomerase
is measured by monitoring incorporation of a nucleotide label
into DNA; the activity of the telomerase enzyme is measured by
monitoring the change in rate of incorporation of nucleotides
into the DNA; the activity of the telomerase enzyme can also be
measured by monitoring the accumulation or loss of nucleotides
into the DNA; the activity of the telomerase enzyme and mTERT
can be further measured by monitoring the loss of the ability to
bind to a telomerase-associated protein; the activity of the
telomerase enzyme and mTERT is measured by monitoring the loss
of the ability to bind to a nucleic acid; and, the activity of
the mTERT is measured by monitoring the loss of the ability to
bind to a chromosome.
[0032] The invention also includes a method where the test
compound produces a statistically significant decrease in the
activity of mTERT as compared to the relative amount of
incorporated label in a parallel reaction lacking the agent,
thereby determining that the agent is a telomerase enzyme or
mTERT inhibitor or activator. The method can be used to
determine if there is a change in telomerase enzyme or TERT
activity using, e.g., a TRAP assay or using a quantitative
polymerase chain reaction assay. The method can determine a
change in telomerase enzyme and mTERT activity by measuring the
accumulation or loss of telomere structure.
[0033] The invention provides for isolated and recombinant
murine proteins and nucleic acids that include murine (mTERT)
specific motifs (see FIGS. 4 and 5) and TERT specific "motifs."
These motifs effect common telomerase structure and function and
uniquely define members of the mTERT species of the invention.
Novel reagents of the invention corresponding to these motif
regions can be used in methods of the invention to generate
unique murine peptides and nucleic acids, including
complementary and antisense hybridization probes and primers, to
identify additional mTERT, including mTERT isoforms, homologues
and alleles.
[0034] Two mTERT proteins are considered to have a statistically
significant sequence identity, i.e., having significant
homology, at the amino acid level in a conserved region of the
TERT protein, such as the motifs described above and in FIGS. 4,
and 5, if, after adjusting for deletions, additions and the
like, the conserved regions have about 20% to 30% sequence
identity, as can be deduced or derived from FIGS. 4 or 5.
However, this sequence identity can be higher, e.g., as high as
about 40% to 50% or higher, if, e.g. the conserved region of
comparison is shorter, i.e., a region of about 5 to about 10
consecutive amino acids. Furthermore, the skilled artisan can
deduce or derive additional mTERT motifs, modifications of these
mTERT motifs, and variations in the amount of sequence identity
in a particular mTERT motif to determine whether a polypeptide
or nucleic acid is a member of the mTERT species of the
invention, and the like, by reference to the teachings and
sequences of the invention, particularly including FIGS. 4 and
5.
[0035] A further understanding of the nature and advantages of
the present invention may be realized by reference to the
remaining portions of the specification, the figures and claims.
BRIEF DESCRIPTION OF THE
FIGURES
[0036] FIG. 1 shows the
complete sequencing of the mouse TERT cDNA (SEQ ID NO:1).
[0037] FIG. 2 shows the
deduced mTERT translation product (SEQ ID NO:2).
[0038] FIG. 3 shows the
alignment of mTERT (SEQ ID NO:2) with hTERT (SEQ ID NO:3).
Positions of motifs are also indicated. Motifs 2 and D are
underlined to help distinguish them from motifs 1 and C,
respectively.
[0039] FIG. 4 shows
mTERT motifs in relation to the sequence conservation between
mTERT motifs and other TERT motifs. Motif alignments from top to
bottom: human (SEQ ID NOS:21-27), mouse (SEQ ID NOS:28-39),
Euplotes aediculatus (SEQ ID NOS:35-42), Saccharomyces
cerevisiae (SEQ ID NOS:43-50), Schizosaccharomyces pombe (SEQ ID
NOS:51-58). Conserved residues are indicated in bold. Consensus
amino acids (TRT con)=(SEQ ID NOS:59-61).
[0040] FIG. 5 shows the
murine, or Mus, specific TERT motif (specifically, Motif T,
Motif 1, Motif 2, Motif A, Motif B', Motif C, Motif D, and Motif
E) sequences of the invention (SEQ ID NOS:78-80, 65, and 70,
respectively) in relation to other TERT amino acid motifs,
(hum=human specific TRT motif=SEQ ID NOS:71-73, 65, 74-77 and
70, respectively; gen=general TRT motif=SEQ ID NOS:62-70,
respectively)
[0041] FIG. 6 shows a
preliminary sequence of the genomic promoter region of mTERT
(SEQ ID NO:4).
[0042] FIG. 7 shows a
schematic of mTERT genomic DNA from the lambda phage genomic
insert, including relevant restriction enzyme cleavage sites and
fragment sizes.
[0043] FIG. 8 shows a
sequence of the genomic promoter region of mTERT (SEQ ID NO:5).
[0044] FIG. 9 presents a
schematic illustration of the mouse gene "knockout" targeting
construct pmTERTKO.
DETAILED DESCRIPTION OF THE
INVENTION
[0045] This invention relates to the cloning and
characterization of the mouse telomerase reverse transcriptase
(mTERT) gene and provides isolated and recombinant mTERT
proteins and nucleic acids. The invention further includes
isolated and recombinant mouse telomerase enzymes and related
methods.
[0046] The present invention provides an isolated (from
synthetic or natural sources) or recombinant mTERT. In other
embodiments, the invention provides for isolated and recombinant
mTERT isoforms, homologues and alleles, and methods for
identifying such mTERT species. In one embodiment, the mTERT is
a protein of about 127 kd, having the sequence of SEQ ID NO:2,
encoded by the cDNA depicted by SEQ ID NO:1.
[0047] The invention also provides for an isolated or
recombinant mouse telomerase enzyme complex comprising at least
one mTERT and a telomerase-associated nucleic acid moiety for
use as a template for DNA synthesis. The telomerase-associated
nucleic acid moiety can be derived from or based on such nucleic
acids found in mice (mTERC) or humans (hTERC). In one
embodiment, the telomerase enzyme complex is comprised of
components of mouse origin, including mTERT encoded by the cDNA
of SEQ ID NO:1, a mouse telomerase-associated RNA (mTERC)
moiety. In another embodiment, the telomerase enzyme complex is
comprised of components of mouse and human origin, including
mTERT encoded by the cDNA of SEQ ID NO:1 and an hTERC moiety.
The mouse telomerase enzyme-associated RNA component (mTERC) has
been cloned and characterized, see U.S. Ser. No. 08/782,787,
filed 10 Feb. 1997; U.S. Ser. No. 08/670,516, filed 27 Jun.
1996; and U.S. Ser. No. 08/485,778, filed 7 Jun. 1995. In
addition, hTERC (hTR) knockout mice have been constructed, see
U.S. Ser. No. 08/623,166, filed 28 Mar. 1996. hTERC has been
cloned and characterized, see PCT Publication Nos. 96/01835 and
96/40868 and U.S. Pat. No. 5,583,016.
[0048] In alternative embodiments the telomerase can include any
number of enzyme complex-associated proteins, such as
co-purifying proteins and other proteins that regulate enzyme
activity.
[0049] The present invention provides a number of different
methods for expressing and isolating mTERT, telomerase enzyme
and telomerase-associated compounds that can be employed, in one
or more aspects, as reagents and are useful in methodologies as
described herein. The novel reagents and methods of the
invention provide for mice lacking in full or partial mTERT
activity, i.e., mTERT "knockout" mice, and methods for making
such mice.
[0050] The telomerase-associated protein can be, for example,
the mouse homologue of the Tetrahymena p80 protein, described in
Harrington (1997) Science 275:973. While some
telomerase-associated proteins are known, the present invention
provides methods and reagents for identifying additional
telomerase enzyme-associated proteins and other compounds and
assembling (i.e, "reconstituting") them with mTERT. Such
telomerase enzyme-associated proteins can be prepared in
accordance with, e.g., U.S. Ser. No. 08/883,377 and PCT
application No. 97/06012, both filed Apr. 4, 1997; and PCT
application No. 96/14679, U.S. Ser. No. 08/710,249 and
08/713,922, all filed Sep. 13, 1996. The Tetrahymena p80 and p95
putative telomerase proteins are described in PCT publication
No. 96/19580.
[0051] The invention, providing for mTERT isoforms, homologues
and alleles, describes structural features common to the mTERT
species of the invention in the form of structural motifs, see
FIGS. 4 and 5. These motifs can effect common mTERT and
telomerase enzyme functions. Sequence analysis of mTERT shows
that it contains murine-specific amino acid regions, i.e.,
"motifs," common to other mTERT proteins, as illustrated in FIG.
5.
[0052] Novel reagents of the invention corresponding to these
motif regions can be used in methods of the invention to
generate antibodies and to identify additional mTERT isoforms,
homologues and alleles. The invention provides oligonucleotides
corresponding to these motif regions, including restriction
enzyme fragments and amplification products generated from an
mTERT. Oligonucleotides corresponding to motifs can also be
synthesized in vitro. These oligonucleotides can also be used as
PCR amplification primers or hybridization probes to identify
and isolate additional mouse isoforms, homologues and alleles.
These oligonucleotides can also be used as primers to amplify
additional mTERT species, using techniques such as RACE, as
described below.
[0053] The invention further provides for an isolated, purified
or recombinant mouse telomerase enzyme complex capable of
replicating telomeric DNA or any sequence determined by a
telomerase enzyme-associated nucleic acid component. The
telomerase enzyme complex of the invention can comprise
components that are purified or isolated from a natural or
synthetic source, a recombinantly manufactured.
[0054] The mTERT of the complex can be modified to delete the
full or a "partial activity" of the TERT or enzyme complex, as
described below.
[0055] Telomerase reverse transcriptase enzymes and mTERT are
very rare in nature, and few successful attempts have been made
to purify the enzyme complex; see, as examples of such
successful purification, U.S. Ser. No. 08/510,736, filed Aug. 4,
1995, and U.S. Ser. No. 08/833,377, and PCT application No.
97/06012, both filed Apr. 4, 1997. The aforementioned patent
applications provide useful methodologies and reagents that can
be applied to the methods and reagents of the present invention.
The present invention provides a variety of methods and reagents
for creating the most pure mouse telomerase enzyme and mTERT
preparations ever made, including methods for making recombinant
telomerase enzyme and mTERT in abundant levels in recombinant
host cells, methods for producing telomerase enzyme and mTERT
synthetically and in cell-free translation systems. The
invention provides methods for isolating recombinant or native
telomerase enzyme, mTERT and telomerase components by reacting
the telomerase or mTERT with an anti-telomerase antibody of the
invention.
[0056] Also provided are methods and compositions for the
expression of the mouse telomerase enzymes and mTERTs of the
invention. In alternative embodiments, the compositions of the
invention are expressed as fusion proteins comprising exogenous
sequences to aid in cell targeting, purification, expression
and/or detection of mTERT and telomerase enzyme. The recombinant
telomerase enzyme, mTERTs and telomerase-associated compositions
of the invention can be independently or co-expressed in any
system, including bacteria, yeast, fungi, insect or mammalian
cells or the whole organism. The telomerase enzymes and mTERTs
of the invention can also be expressed ex vivo, or in vivo,
e.g., as in transgenic non-human animals.
[0057] The invention also provides for methods of reconstituting
telomerase enzyme and mTERT activity, including fill and partial
activity, in vitro and in vivo, using the purified mTERT of the
invention, with or without further incorporation of its RNA
moiety or telomerase-associated components. As used herein, the
term reconstitution of a telomerase activity in a cell or animal
also includes inducement, augmentation or replacement of low,
lost or "knocked out" telomerase enzyme or mTERT activity. In
one embodiment, the method can reconstitute "full" telomerase
activity, ie., the ability to synthesize telomere DNA.
Alternatively, the reconstitution can be only for "partial
activities," as described in detail below. The invention include
reconstitution of hTERT in such mTERT "knockout" mice, and the
animals and their progeny produced by such reconstitution. The
cloning and characterization of hTERT is described, e.g., in
U.S. Ser. No. 08/854,050, filed May 9, 1997; in U.S. Ser. No.
08/915,503, U.S. Ser. No. 08/912,951, and, U.S. Ser. No.
08/911,312, all filed Aug. 14, 1997; and in U.S. Ser. No.
08/974,549, and U.S. Ser. No. 08/974,584, both filed on Nov. 19,
1997.
[0058] The assays of the invention can be used to assess the
degree of purification, identify a new mTERT species, such as an
mTERT allele, homologue, or isoform, or to screen for modulators
(antagonists and agonists) of telomerase-mediated DNA
replication. Methods for identifying modulators of a telomerase
enzyme activity have been described in U.S. Pat. No. 5,645,986;
and U.S. Ser. No. 08/151,477, filed Nov. 12, 1993; and U.S. Ser.
No. 08/288,501, filed Aug. 10, 1994, and the reagents of the
invention may be employed in such methods. Antagonists and
agonists of mTERT can be used to modify the activity of other
telomerase enzymes, such as hTERT (hTRT).
[0059] The invention contemplates screening for compositions
capable of modifying the polymerase activity of telomerase
enzyme, or a partial activity, by any means. In various
embodiments, the invention includes: screening for antagonists
that bind to mTERT's active site or interfere with transcription
of its RNA moiety, as mTERC; screening for compositions that
inhibit the association of nucleic acid and/or
telomerase-associated compositions, such as the association of
mTERC with mTERT or the association of mTERT with mouse
p80-homologue or other telomerase-associated proteins, or
association of mTERT with a telomere, chromosome, nucleosome or
a nucleotide; screening for compositions that promote the
dissociation or promote the association of the enzyme complex,
such as an antibody directed to mTERC or mTERT; screening for
agents that effect the processivity of the enzyme; and screening
for nucleic acids and other compositions that bind to mTERT,
such as a nucleic acid complementary to mTERC. The invention
further contemplates screening for compositions that increase or
decrease the transcription of the mTERT gene and/or translation
of the mTERT gene product. These compositions can be used to
modify the transcription or translation of other TERT genes,
such as hTERT.
[0060] Screening for antagonist activity provides for
compositions that decrease telomerase replicative capacity,
thereby limiting the proliferative, replicative potential of
indefinitely proliferating cells, or mortalizing otherwise
immortal cells, such as cancer cells.
[0061] Screening for agonist activity or transcriptional or
translational activators provides for compositions that increase
the telomerase enzyme's telomere replicative capacity, or,
alternatively, a partial activity as described herein. Such
agonist compositions provide for methods of creating
indefinitely proliferating cells, and immortalizing or
increasing the proliferative capacity of otherwise normal,
untransformed cells, including cells which can express useful
proteins. Such agonists can also provide for methods of
controlling cellular senescence, see co-pending U.S. Ser. Nos.
08/912,951 and 08/915,503.
[0062] The novel telomerase compositions and activity
reconstitution assays of the invention also provide for a novel
telomerase repeat amplification protocol assay (TRAP) and
variations of this assay. The TRAP assay is an
amplification-based method for detecting, determining, and
measuring telomerase activity and is described in PCT
Publication Nos. 97/15687 and 95/13381 and U.S. Pat. No.
5,629,154; see also U.S. Ser. No. 08/632,662, and U.S. Ser. No.
08/631,554, filed 15 Apr. 1996 and 12 Apr. 1996, respectively.
See also, Kim (1994) supra. The present invention provides
reagents useful for the TRAP assay as well as new
amplification-based telomerase activity assays for a wide
variety of applications. For example, TRAP assays comprising an
mTERT protein or a telomerase enzyme complex of the invention
can be used to screen for modulators of telomerase activity.
Such compositions can also be used to modulate the activity of
other telomerase enzymes, such as hTERT, or to act as a basis
for identification of such human telomerase enzyme modulators.
[0063] The novel telomerase compositions of the invention can
also be used in telomere length assays. Because of the
relationship between telomerase activity and telomere length,
the diagnostic and therapeutic methods of the invention can be
used in conjunction with telomere length assays. A variety of
telomere length assays have been described, see PCT Patent
publication Nos. 93/23572, 95/13382, 95/13383, and 96/41016, and
U.S. Ser. No. 08/660,402, filed 6 Jun. 1996; 08/479,916, filed
Jun. 7, 1995; and, 08/475,778 and 08/487,290, both filed Jun. 7,
1995.
[0064] The invention provides a method of screening for
telomerase modulators in animals by reconstituting a telomerase
activity, or an anti-telomerase activity, into an animal, such
as a transgenic, non-human animal. The invention provides for in
vivo assays systems that include mouse "knockout" models in
which the endogenous mTERT has been deleted, altered, or
inhibited. The endogenous mTERT can be deleted, altered, or
inhibited in either one or both endogenous mTERT alleles. One
embodiment provides for a telomerase deficient mouse, or mTERT
"knockout" mouse, and its progeny. Other embodiments provide for
"knockout" mice, and their progeny, whose ability to express the
telomerase RNA moiety and/or telomerase-associated proteins has
also been deleted, altered, or modified. In one embodiment, an
exogenous telomerase activity (such as human TERT), or
endogenous mouse telomerase activity, full or partial, wild-type
or modified, is reconstituted in the "knock-out" mouse or
increased in an otherwise normal mouse. In alternative
embodiments, endogenous mouse telomerase enzyme or mTERT
activities, full or partial, can remain either in one or both
alleles. The telomerase activity reconstituted in the "knockout"
mouse model can include modified endogenous or exogenous TERT,
e.g., mTERT or hTERT alone, hTERT and hTERC, mTERT and mTERC,
mTERT and hTERC. The invention also provides for transgenic
cells and animals, in addition to mice, where mTERT and/or
murine telomerase activity has been inserted through recombinant
methodologies. The non-human transgenic animals of the invention
also provide for methods of expressing large amounts of fully or
partially active telomerase enzyme and mTERT. Transgenic animals
also provide for the construction of indefinitely proliferating
cells and the immortalization of otherwise normal cells, which
can then be used, for example, to express compositions of
interest.
[0065] In one embodiment of the invention, recombinant mTERT is
expressed in normal, diploid mortal cells to provide for
indefinitely proliferating cells, immortalization of cells, or
to facilitate long-term culture or replication of the cells.
Telomerase enzyme complex components, such as nucleic acid
telomeric sequence template molecules (mTERC, for example) or
other associated proteins, that are beneficial for expression or
act as modulators of activity, can also be co-expressed. This
invention provides methods to obtain indefinitely proliferating
cells and diploid immortal cells with an otherwise normal
phenotype and karyotype. This aspect of the invention is of
enormous practical and commercial utility; for example, the FDA
and public would value the production of recombinant proteins
from normal cells to minimize concern regarding viral or other
contamination of the products made from such cells as are
commonly used today. The present invention allows one to produce
indefinitely proliferating and immortal hybrids of B lymphocytes
and myeloma cells to obtain hybridomas for monoclonal antibody
production. Using the methods of this invention, transfection of
mTERT protein and telomerase enzyme activity into B lymphocytes
allows one to generate indefinitely proliferating cells and
immortal cells for antibody production.
[0066] Another embodiment provides for methods for introducing
recombinant mTERT and/or telomerase associated RNA and other
compounds of the invention into cells to produce a commercially
desirable protein. For example, by the methods of the invention
an indefinitely proliferating and an immortal, yet
karyotypically normal, pituitary cell that makes hormones, such
as growth hormone, could be produced for commercial use. In a
variation of this embodiment, a normal cell is removed from the
animal, transformed into an indefinitely proliferating cell, or
immortalized, using the methods and reagents of the invention,
transfected with a gene of interest such that the gene is
expressed at appropriate levels and introduced back into the
animal such that the transfected gene expresses a molecule that
impacts the health or other qualities of the animal.
[0067] Another embodiment of the invention involves a similar
method, but the cell is a "universal donor cell" which has been
modified to delete histocompatibility antigens or modified in
some way to prevent or decrease the possibility of immune
rejection. A complication arising from the re-introduction of
these cells into an animal is the possibility that the cells may
lose growth control and change to a state of uncontrolled cell
growth, becoming a cancer, tumor or other malignancy. The
present invention solves this complication by providing means to
express mTERT or other telomerase components conditionally
and/or by providing means for knocking out telomerase enzyme,
mTERT or a telomerase enzyme complex component necessary for
activity. Moreover, even "mortal" cells used in transplantation
or for other purposes can be mortalized by such methods of the
invention. Without an active telomerase, the cells are
irreversibly mortal, thus decreasing the probability of
cancerous or malignant transformation after transplantation or
other re-introduction into a host organism. This would not
affect the cell's function, as telomerase enzyme is not normally
active in somatic cells.
[0068] The present invention also provides methods and reagents
relating to cis-acting transcriptional and translational
regulatory elements. Examples of cis-acting transcriptional
regulatory elements include promoters and enhancers of the mTERT
gene. Examples of cis-acting translational regulatory elements
include elements that stabilize mRNA or protect the transcript
from degradation. The identification and isolation of cis- and
trans-acting regulatory agents provide for further methods and
reagents for identifying agents that modulate transcription and
translation of mTERT and other telomerase enzymes and TERTs,
such as hTERT. While many aspects of these methods and reagents
are described more fully below, U.S. Ser. No. 08/714,482, filed
Sep. 16, 1996, provides useful information relating to reagents
and screens for the hTERC (hTR) promoter that usefully
supplements understanding of certain embodiments of the present
invention relating to the mTERC promoter and isolated and
recombinant molecules comprising all or part of the mTERT
promoter and related methods.
[0069] The present invention also provides novel methods and
reagents for immunizing animals to generate an anti-murine
telomerase enzyme and an anti-mTERT immune response. While these
methods and compositions are fully described below, see also
U.S. Ser. No. 08/734,052, filed Oct. 18, 1996, for additional
useful information.
1. Nucleic Acids Encoding
mTERTs
[0070] This invention for the first time provides the
identification, cloning and characterization of the mTERT gene,
related polypeptide, and telomerase enzyme complexes including,
as well as providing novel reagents including or derived from
these new compositions that complement this significant
achievement.
[0071] The invention provides for novel means of expressing
mTERT in vitro, ex vivo, and in vivo, thereby providing a means
to increase or decrease endogenous or exogenous TERT expression
and activity. These novel means of expressing mTERT also provide
for in vitro, ex vivo, and in vivo assays to screen for
telomerase activity modulators, including agonist and
antagonists. Screening for agonist and antagonist activity
further provides for compositions that can decrease or increase
the telomerase enzyme and TERT's ability to extend telomeres,
i.e., telomere replicative capacity. Agonist compositions and
methods for creating indefinitely proliferating cells and
immortalizing otherwise normal, untransformed cells, thereby
extending cell life, including cells which can express useful
proteins and other compounds, are also provided. Such agonists
and methods provide a means to control cellular senescence and
so ameliorate the diseases associated with aging and
debilitating conditions.
[0072] Telomerase activity has been identified as an important
cancer marker, one whose levels can predict the outcome or
seriousness of disease, as described in U.S. Pat. Nos.
5,489,508; 5,648,125 and 5,639,613. Antagonist compositions,
means for screening for such compositions and methods for
inhibiting mTERT and telomerase enzyme in continuously
proliferating, transformed and immortal cells, thereby
shortening cell life, thus are also provided by the invention.
Antagonists of mTERT can also be antagonists of hTERT.
[0073] In another embodiment, the novel compositions of the
invention, including mTERT-encoding nucleic acids and anti-mTERT
antibodies, can also be used to identify and purify mTERT
isoforms, homologues, and alleles. In an alternative embodiment,
mTERT and known telomerase enzyme complex components are used to
identify additional telomerase-associated components. In one
embodiment, the nucleic acids of the invention are used to
reconstitute mTERT activity in vitro, ex vivo, or in vivo. The
nucleic acids of the invention can also be used modify the
activity of mTERT, as for example, the invention provides
antisense nucleotide sequences, telomerase-inhibiting ribozymes,
dominant negative mTERT proteins, and gene therapy vectors
encoding the same.
[0074] The invention also provides for methods and associated
reagents incorporating the nucleic acids of the invention that
include or can be used to identify mTERT-specific cis-acting
transcriptional control elements, such as mTERT promoters, and
trans-acting elements that bind to such sequences.
[0075] The invention can be practiced in conjunction with any
method or protocol known in the art, which are well described in
the scientific and patent literature. Therefore, only a few
general techniques will be described prior to discussing
specific methodologies and examples relative to the novel
reagents and methods of the invention.
[0076] a. General Techniques
[0077] The mTERT, telomerase enzyme and telomerase-associated
nucleic acids of this invention, whether RNA, cDNA, genomic DNA,
or a hybrid thereof, or synthetically prepared using
non-naturally occurring reagents, may be isolated from a variety
of sources or may be synthesized in vitro. Nucleic acids coding
for the protein compositions of the invention can be expressed
in transgenic animals, transformed cells, in a cell lysate, or
in an isolated, partially purified or a substantially pure form.
Techniques for nucleic acid manipulation of genes encoding the
mTERT species of the invention, such as generating libraries,
subcloning into expression vectors, labeling probes, sequencing
DNA, and DNA hybridization are described generally in Sambrook,
ed., MOLECULAR CLONING: A LABORATORY MANUAL (2ND ED.), Vols.
1-3, Cold Spring Harbor Laboratory, (1989) ("Sambrook"); CURRENT
PROTOCOLS IN MOLECULAR BIOLOGY, Ausubel, ed. John Wiley &
Sons, Inc., New York (1997) ("Ausubel"); LABORATORY TECHNIQUES
IN BIOCHEMISTRY AND MOLECULAR BIOLOGY: HYBRIDIZATION WITH
NUCLEIC ACID PROBES, Part I. Theory and Nucleic Acid
Preparation, Tijssen, ed. Elsevier, N.Y. (1993) ("Tijssen").
Sequencing methods typically can include dideoxy sequencing
(Sequenase, U.S. Biochemical), however, other kits and methods
are available and well known to those of skill in the art.
[0078] Nucleic acids and proteins are detected and quantified in
accordance with the teachings and methods of the invention
described herein by any of a number of general means well known
to those of skill in the art. These include, for example,
analytical biochemical methods such as spectrophotometry,
radiography, electrophoresis, capillary electrophoresis, high
performance liquid chromatography (HPLC), thin layer
chromatography (TLC), and hyperdiffusion chromatography, various
immunological methods, such as fluid or gel precipitin
reactions, immunodiffusion (single or double),
immunoelectrophoresis, radioimmunoassays (RIAs), enzyme-linked
immunosorbent assays (ELISAs), immuno-fluorescent assays, and
the like, Southern analysis, Northern analysis, Dot-blot
analysis, gel electrophoresis, RT-PCR, quantitative PCR, other
nucleic acid or target or signal amplification methods,
radiolabeling, scintillation counting, and affinity
chromatography, to name only a few.
[0079] b. Isolation, Synthesis,
and Purification of Nucleic Acids Encoding mTERT
[0080] In another embodiment, the invention provides methods to
identify and isolate mTERT isoforms, homologues, and alleles.
The invention provides a recitation of structural features
common to mTERT species of the invention, ie., motifs which are
mTERT specific and motifs which can be used to identify
additional mTERT species (see FIGS. 4 and 5). The murine, or
Mus, specific TERT motif (specifically, Motif T, Motif 1, Motif
2, Motif A, Motif B', Motif C, Motif D, and Motif E) sequences
of the invention are shown in FIG. 5.
[0081] Typically, TERTs are large, basic, proteins having
telomerase-specific amino acid motifs, some of which are reverse
transcriptase (RT) motifs, as disclosed herein. Because these
motifs are conserved across diverse organisms, additional murine
TERT mRNA, cDNA and genes can be obtained or identified using
primers, nucleic acid probes, and antibodies to one or more of
the motif sequences.
[0082] Sequence analysis of mTERT shows that it contains amino
acid regions, or motifs, that identify it as a reverse
transcriptase (RT) enzyme. FIGS. 3, 4, and 5, show the alignment
of mTERT with other TERT proteins. The RT region is in the
approximately middle third of the mTERT mRNA (cDNA, SEQ ID
NO:1), is the most structurally conserved region of mTERT as
compared to RTs from other organisms. Thus, in one embodiment,
the nucleic acids comprising this and the other motifs
(described in FIGS. 4 and 5) can be used as probes to identify
additional mTERT species. In an alternative embodiment, primers
able to amplify these motif-encoding regions can directly
generate new mTERT species, or generate nucleic acids to be used
as hybridization probes for such mTERT specie identification. In
another embodiment, nucleic acids comprising regions poorly
conserved between TERTs, particularly hTERT, can be used to
identify TERTs closely related to mouse mTERT, such as those
from other rodent species. Alternatively, motif regions can be
excised by restriction enzyme digestion for use as hybridization
probes, as described below. Probes targeting mTERT motifs can
also be produced synthetically.
[0083] The motifs found in TERTs, while similar to those found
in other reverse transcriptases, have particular hallmarks. For
example, in motif C the two aspartic acid residues (DD) that
coordinate active site metal ions (see, Kohlstaedt (1992)
Science 256:1783; Jacobo-Molina (1993) Proc. Natl. Acad. Sci.
USA 90:6320; Patel (1995) Biochemistry 34:5351) occur in the
context hxDD(F/Y) (SEQ ID NO:85) in the telomerase RTs compared
to (F/Y)xDDh (SEQ ID NO:86) in the other RTs (where h is a
hydrophobic amino acid, and "x" is any amino acid; see Xiong
(1990) EMBO J. 9:3353; Eickbush, in The Evolutionary Biology of
Viruses (S. Morse, Ed., Raven Press, N.Y., p. 121, 1994).
Another systematic change characteristic of the telomerase
reverse transcriptase enzymes occurs in motif E, where WxGx (SEQ
ID NO:87) is a consensus among the telomerase proteins, whereas
hLGxxh (SEQ ID NO:88) is characteristic of other RTs (Xiong,
supra; Eickbush supra). This motif E is called the "primer grip"
(Jacobo-Molina (1993) supra, Wohrl (1997) J. Biol. Chem.
272:17581-17587) and mutations in this region affect priming in
RNA polymerases but not priming in DNA polymerases (Powell
(1997) J. Biol. Chem. 272:13262). In addition, the distance
between motifs A and B' is longer in the TERTs than is typical
for other RTs, which may be accommodated as an insertion within
the "fingers" region of the structure which resembles a right
hand (see Kohlstaedt, supra; Jacobo-Molina, supra; and Patel,
supra).
[0084] The T motif ("motif T") is an additional hallmark of TERT
proteins (see FIGS. 3 and 4). The T motif comprises a sequence
that can be described using the formula:
W-X12-FFY-X-T-E-X10-11-R-X3-W (SEQ ID NOS:89 and 90), or,
alternatively described using the formula:
Trp-R1-X7-R1-R1-R2-X-Phe-Phe-Tyr-X-Thr-Glu-X8-9R3-R3-Arg-R4-X2-Trp
SEQ ID NOS:91 and 92), where X is any amino acid and the
subscript refers to the number of consecutive residues, R1 is
leucine or isoleucine, R2 is glutamine or arginine, R3 is
phenylalanine or tyrosine, and R4 is lysine or histidine.
[0085] The T motif can also be described using the formula:
Trp-R1-X4-h-h-X-h-h-R2-p-Phe-Phe-Tyr-X-Thr-Glu-X-p-X3-p-X2-3-R3-R3-R3-Arg-R4-X2-Trp
(SEQ
ID NOS:62 and 63) where X is any amino acid, a subscript refers
to the number of consecutive residues, R1 is leucine or
isoleucine, R2 is glutamine or arginine, R3 is phenylalanine or
tyrosine, R4 is lysine or histidine, h is a hydrophobic amino
acid selected from Ala, Leu, Ile, Val, Pro, Phe, Trp, and Met,
and p is a polar amino acid selected from Gly, Ser, Thr, Tyr,
Cys, Asn and Gln.
[0086] Motif 1 can also be described using the formula:
L-R-X2-P-K-X3 (SEQ ID NO:93), or, alternatively, h-R-h-I-P-K-X3
(SEQ ID NO:94).
[0087] Motif 2 can also be described using the formula:
X-R-X-I-X (SEQ ID NO:95), or, alternatively (F/L)-R-h-I-X2-h
(SEQ ID NO:65).
[0088] Motif A can also be described using the formula:
X4-F-X3-D-X4-Y-D-X2 (SEQ ID NO:96), alternatively
P-X-L-Y-F-h-X-h-D-h-X3-Y-D-X-I (SEQ ID NO:97)
[0089] Motif B' can also be described using the formula:
Y-X4-G-X2-Q-G-X3-S-X8 (SEQ ID NO:98), or, alternatively
Q-X2-G-I-P-Q-G-S-X-L-S-X-h-L (SEQ ID NO:99).
[0090] Motif C can also be described using the formula:
X6-D-D-X-L-X3 (SEQ ID NO:100), or, alternatively,
L-L-R-F-X-D-D-F-L-L-X-T (SEQ ID NO:101).
[0091] It will be apparent to one of skill that, provided with
the reagents, and the mTERT sequences disclosed herein for those
reagents, and the methods and guidance provided herein
(including specific methodologies described infra), mTERT genes
and proteins can be obtained, isolated and produced in
recombinant form by one of ordinary skill. For example, primers
(e.g., degenerate amplification primers) are provided that
hybridize to gene sequences encoding motifs characteristic of
mTERT species to identify further mTERT isoforms, homologues,
and alleles. One or more primers or degenerate primers that
hybridize (as discussed infra) to sequences encoding the above
described mTERT motifs, or combinations of such motifs or TERT
consensus sequence (as shown in FIGS. 4 and 5), can be prepared
based on the codon usage of the target organism, and used to
amplify the mTERT gene sequence from genomic DNA or cDNA
prepared from the target organism. Use of degenerate primers is
well known in the art and entails sets of primers that hybridize
to the set of nucleic acid sequences that can potentially encode
the amino acids of the target motif, taking into account codon
preferences and usage of the target organism, and by using
amplification (e.g., PCR) conditions appropriate for allowing
base mismatches in the annealing steps. Typically two primers
are used; however, single primer (or, in this case, a single
degenerate primer set) amplification systems are well known and
may be used to obtain mTERT encoding nucleic acids.
[0092] The T motif is necessary for at least one of telomerase's
activity, including enzymatic catalysis. The mTERT of the
invention and fragments thereof which include the T motif
provide for a preferred nucleic acid or amino acid sequence or
subsequence to be used in methods of the invention, including,
for example, methods for identifying and isolating mTERT
alleles, isoforms, and homologues, or, as described below, for
making dominant negative mutant constructs, see below.
[0093] The mTERTs of the invention can also be identified,
isolated and expressed using methods of the invention,
including: i) computer searches of murine DNA databases for DNAs
containing sequences conserved with an mTERT specie and having
sequence identity with TERT motifs and mTERT sequences described
above, ii) hybridization with a probe from a known mTERT
sequence to mouse mRNA, cDNA or RT DNA sequence or murine cDNA
or genomic libraries, and iii) by PCR or other signal or target
amplification technologies of mouse nucleic acid using primers
complementary to regions highly conserved among different TERTs,
such as the motifs of the invention. Amino acid sequences can be
conserved, but, because of the degeneracy of the genetic code,
codon usage bias, or amino acid changes, the DNA sequences
corresponding to motif regions can be different between
organisms. For this reason, one can employ in the methods
nucleotides at the positions in the primers that are degenerate
for a particular amino acid to ensure that one or more of the
different primers can hybridize to an mTERT whose nucleotide
sequence is not completely known. In performing PCR with such
primers, one may take allowances for the degenerate positions
probe by using conditions appropriate for allowing certain base
mismatches to occur in the annealing steps of PCR, i.e.,
degenerate PCR conditions. Primers of the invention are used to
identify murine mTERT species encompassed by the invention.
[0094] While methods for isolating total DNA or RNA are well
known to those of skill in the art, e.g., see Tijssen and
Sambrook, illustrative example of methods for identifying,
characterizing and isolating mTERT nucleic acids of the
invention are provided below.
[0095] i. Preparation and
Screening of TERT-encoding DNA Libraries
[0096] There are numerous methods for isolating DNA sequences
encoding the mTERT of the invention. For example, mTERT DNA can
be identified by stringent hybridization and isolated from a
murine genomic or cDNA library using oligonucleotide probes,
typically labeled, having sequences complementary to mTERT
sequences or subsequences, such as TERT motifs, as disclosed
herein. For example, the mTERT encoded by the genomic and cDNA
nucleic acid whose sequence is set forth in SEQ ID NO:1, can be
used to construct such probes or primers. Such probes can be
used directly in hybridization assays to isolate DNA encoding
mTERT species. Alternatively probes can be designed for use in
amplification techniques such as PCR.
[0097] The invention provides compositions and methods to screen
both genomic and cDNA libraries for mTERT sequences. Screening
cDNA libraries for coding sequences has certain advantages in
that no intronic sequences are usually present. Screening
genomic libraries has an advantage in that upstream and
downstream cis-acting transcriptional regulatory elements can be
identified and isolated, as well as introns, promoters and
enhancers which may be beneficial to include in some expression
vectors. Furthermore, in some species, the intronic or
untranscribed mTERT sequences may be the most conserved.
Accordingly, the invention provides for the isolation of mTERT
genomic nucleic acids, including introns, protein-encoding
exons, and transcribed and non-transcribed genomic sequences as
additional reagents and means to identify and screen for mTERT
isoforms, alleles and homologues.
[0098] Identification of mTERT cis-acting regulatory elements
provides reagents and means to isolate further mTERT
trans-acting regulatory compounds. Identification of such mTERT
regulatory elements provides the means to design TERT modulating
compounds which can be used to up- or down-regulate TERT
transcription, translation, or assembly of a functional or
partially functional (i.e., having "partial activity") TERT or
telomerase enzyme. The invention also provides isolated and
recombinant nucleic acids comprising the mouse genomic promoter
region, as described below, and identified in SEQ ID NO:1.
[0099] To prepare a cDNA library, mRNA is isolated, reverse
transcribed and inserted into vectors in accordance with general
procedures well known in the art. The vectors are transfected
into a recombinant host for propagation, screening and other
applications. Methods for making and screening cDNA libraries
are well known, see e.g, Gubler (1983) Gene 25:263-269; Shepard
(1997) Nucleic Acids Res. 25:3183-3185; Davis (1997) Proc. Natl.
Acad. Sci. USA 94:2128-2132; Alphey (1997) Biotechniques
22:481-484; and Sambrook. To make a genomic library, total DNA
is extracted and purified by well-known methods (see, e.g.,
Sambrook, Ausubel). DNA of appropriate size is produced by known
methods, such as mechanical shearing or enzymatic digestion, to
yield DNA fragments, e.g., of about 12 to 20 kb. The fragments
are then separated, as for example, by gradient centrifugation,
or gel electrophoresis, from undesired sizes. Selected fragments
can be inserted in bacteriophage or other vectors. These vectors
and phage can be packaged in vitro, as described, e.g., in
Sambrook. Recombinant phage can be analyzed by plaque
hybridization as described, e.g., in Benton (1977) Science
196:180; Chen (1997) Methods Mol Biol 62:199-206. Colony
hybridization can be carried out as generally described in the
scientific literature, e.g., as in Grunstein (1975) Proc. Natl.
Acad. Sci. USA 72:3961-3965; Yoshioka (1997) J. Immunol Methods
201:145-155; Palkova (1996) Biotechniques 21:982.
[0100] DNA encoding an mTERT isoform, homologue, or allele can
be identified in either murine cDNA or genomic libraries by
hybridization with nucleic acid probes of the invention, e.g.,
probes containing 10 to 20 to 50 or more contiguous nucleotides
of SEQ ID NO:1, on Southern blots. Once identified, these DNA
regions are isolated by standard methods familiar to those of
skill in the art. Alternatively, RNA encoding mTERT protein may
be identified by hybridization to nucleic acid probes in
Northern blots or other formats; see, e.g., Sambrook for general
procedures relating to such formats.
[0101] Oligonucleotides for use as probes can be chemically
synthesized, as described below. Synthetic nucleic acids,
including oligonucleotide probes and primers, mTERT coding
sequences, antisense, ribozymes and the like can be prepared by
a variety of solution or solid phase methods. Detailed
descriptions of the procedures for solid phase synthesis of
nucleic acids by phosphite-triester, phosphotriester, and
H-phosphonate chemistries are widely available. For example, the
solid phase phosphoramidite triester method of Beaucage and
Carruthers using an automated synthesizer is described in
Itakura, U.S. Pat. No. 4,401,796; Carruthers, U.S. Pat. Nos.
4,458,066 and 4,500,707; Carruthers (1982) Genetic Engineering
4:1-17; see also Needham-VanDevanter (1984) Nucleic Acids Res.
12:6159-6168; Beigelman (1995) Nucleic Acids Res 23: 3989-3994;
Jones, chapt 2, Atkinson, chapt 3, and Sproat, chapt 4, in
OLIGONUCLEOTIDE SYNTHESIS: A PRACTICAL APPROACH, Gait (ed.), IRL
Press, Washington D.C. (1984); Froehler (1986) Tetrahedron Lett.
27:469-472; Froehler, Nucleic Acids Res. 14:5399-5407 (1986);
Sinha, Tetrahedron Lett. 24:5843-5846 (1983); and Sinha, Nucl.
Acids Res. 12:4539-4557 (1984); for synthesis of fluorescently
labeled oligonucleotides and their application in DNA
sequencing, see Markiewicz (1997) Nucleic Acids Res.
25:3672-3680; Shchepinov (1997) Nucleic Acids Res. 25:4447-4454,
describing synthesis of a phosphoramidite synthon.
[0102] Methods to purify oligonucleotides include, for example,
native acrylamide gel electrophoresis, anion-exchange HPLC, as
described in Pearson (1983) J. Chrom. 255:137-149, and Ausserer
(1995) Biotechniques 19:136-139; Arghavani (1995) Anal. Biochem.
231:201-209, using reversed-phase high-performance liquid
chromatography, and the like. The sequence of the synthetic
oligonucleotide can be verified using any chemical degradation
method, e.g., see Maxam (1980) Methods in Enzymol. 65:499-560,
Xiao (1996) Antisense Nucleic Acid Drug Dev. 6:247-258; or for
solid-phase chemical degradation procedures, see e.g., Rosenthal
(1987) Nucleic Acids Symp. Ser. 18:249-252; to sequence
phosphorothioate DNA, see Froim (1997) Nucleic Acids Res.
25:4219-4223.
[0103] ii. Amplification of
Nucleic Acids Encoding TERT and Telomerase
[0104] The present invention provides oligonucleotide primers
and probes that can hybridize specifically to nucleic acids
having mTERT protein-encoding cDNA or genomic nucleic acid, such
as the mTERT sequence of SEQ ID NO:1, encoding the polypeptide
of SEQ ID NO:2. Such reagents can be used to identify any
species of mTERT protein-encoding and genomic sequences. mTERT
genomic sequences include intronic and genomic, non-transcribed
sequences, promoters, and enhancers which can also be amplified
using the PCR primers of the invention to identify new mTERT
isoforms, alleles and homologues. Illustrative PCR primers and
amplification methods are described below.
[0105] Amplification of mTERT sequences which are conserved
amongst different mTERT species, i.e., consensus or motif mTERT
sequences, as described above, can be used to generate
oligonucleotides that are preferred reagents of the invention.
The reagents are used as hybridization probes to identify and
isolate additional mTERT species. These oligonucleotides can
also be used as primers to amplify additional mTERT species
directly, using any amplification technique, such as, for
example RACE, as described below.
[0106] Oligonucleotides can be used to identify and detect
additional mTERT species using a variety of hybridization
techniques and conditions. One of skill in the art will
appreciate that, whatever amplification method is used, if a
quantitative result is desired, care must be taken to use a
method that maintains or controls for the relative frequencies
of the amplified nucleic acids. Suitable amplification methods
include, but are not limited to: polymerase chain reaction, PCR
(PCR PROTOCOLS, A GUIDE TO METHODS AND APPLICATIONS, ed. Innis,
Academic Press, N.Y. (1990) and PCR STRATEGIES (1995), ed.
Innis, Academic Press, Inc., N.Y. ("Innis")), ligase chain
reaction (LCR) (Wu (1989) Genomics 4:560; Landegren (1988)
Science 241:1077; Barringer (1990) Gene 89:117); transcription
amplification (Kwoh (1989) Proc. Natl. Acad. Sci. USA 86:1173);
self-sustained sequence replication (Guatelli (1990) Proc. Natl.
Acad. Sci. USA, 87:1874); Q Beta replicase amplification (Smith
(1997) J. Clin. Microbiol. 35:1477-1491, automated Q-beta
replicase amplification (Burg (1996) Mol. Cell. Probes
10:257-271); and other RNA polymerase mediated techniques (e.g.,
NASBA, Cangene, Mississauga, Ontario); see also Berger (1987)
Methods Enzymol. 152:307-316, Sambrook, and Ausubel, as well as
Mullis (1987) U.S. Pat. Nos. 4,683,195 and 4,683,202; Arnheim
(1990) C&EN 36-47; Lomell (1989) J. Clin. Chem. 35:1826; Van
Brunt (1990) Biotechnology 8:291-294; Wu (1989) Gene 4:560; and
Sooknanan (1995) Biotechnology 13:563-564. Methods for cloning
in vitro amplified nucleic acids are described in Wallace, U.S.
Pat. No. 5,426,039.
[0107] The invention provides for amplification and manipulation
or detection of the products from each of the above methods to
prepare DNA encoding mTERT protein or otherwise identical or
complementary mTERT gene sequences. In PCR techniques,
oligonucleotide primers complementary to the two borders of the
DNA region to be amplified are synthesized and used (see, e.g.,
Innis). PCR can be used in a variety of protocols to amplify,
identify, isolate and manipulate nucleic acids encoding mTERT.
In these protocols, appropriate primers and probes for
identifying and amplifying DNA encoding mTERT polypeptides and
fragments thereof are generated that comprise all or a portion
of any of the DNA sequences listed herein. PCR-amplified
sequences can also be labeled and used as detectable
oligonucleotide probes, but such nucleic acid probes can be
generated using any synthetic or other technique well known in
the art.
[0108] The present invention provides RACE-based methods for
isolating mTERT nucleic acids. RACE is another PCR-based
approach for DNA amplification. Briefly, this technique involves
using PCR to amplify a DNA sequence using an introduced random
5' primer and a gene-specific 3' primer (5' RACE) or an
introduced random 3' primer and a gene specific 5' primer (3'
RACE). The amplified sequence is then subcloned into a vector
where can be sequenced and manipulated using standard
techniques. The RACE method is well known to those of skill in
the art and kits to perform RACE are commercially available,
e.g. Gibco BRL, Gaithersburg, Md., #18374-058 (5' RACE) or
#18373-019 (3' RACE), see also Lankiewicz (1997) Nucleic Acids
Res 25:2037-2038; Frohman (1988) Proc. Natl. Acad. Sci. USA
85:8998; and Doenecke (1997) Leukemia 11:1787-1792.
[0109] For 5' RACE, a primer, the gene-specific primer, is
selected near the 5' end of the known sequence oriented to
extend towards the 5' end. The primer is used in a primer
extension reaction using a reverse transcriptase and mRNA. After
the RNA is optionally removed, the specifically-primed cDNA is
either: 1) "tailed" with deoxynucleotide triphosphates (dNTP)
and dideoxyterminal transferase; then a primer that is
complementary to the tail with a 5' end that provides a unique
PCR site and the first gene-specific primer is used to PCR
amplify the cDNA; subsequent amplifications are usually
performed with a gene-specific primer nested with respect to the
first primer, or 2) an oligonucleotide that provides a unique
PCR site is ligated to an end of the cDNA using RNA ligase; then
a primer complimentary to the added site and the first
gene-specific primer is used to PCR amplify the cDNA, with
subsequent amplifications usually performed with a gene-specific
primer nested with respect to the first primer. Amplified
products are then purified, usually by gel electrophoresis, then
sequenced and the sequence examined to determine if the products
contain the additional cDNA sequences desired.
[0110] For 3' RACE, an oligo dT-primer is annealed to the poly-A
tails of an mRNA and then extended by a reverse transcriptase.
Usually the oligo dT primer has a 5' end that provides a unique
PCR site. The RNA is then removed, optionally, or dissociated,
and the cDNA is amplified with a primer to the oligo dT tail and
a gene-specific primer near the 3' end of the known sequence
(oriented towards the 3' end). Subsequent amplifications are
usually performed with a gene-specific primer nested with
respect to the first primer. Amplified products are then
purified, usually by gel electrophoresis, then sequenced and
examined to determine if the products contain the additional
cDNA sequences desired.
[0111] Another useful means of obtaining nucleic acids of the
invention, such as large genomic clones, is to screen BAC or P1
murine genomic libraries. BACs, bacterial artificial
chromosomes, are vectors that can contain 120+ Kb inserts (for
example, see Asakawa (1997) Gene 191:69-79, for a description of
the construction and of a human BAC library. BACs are based on
the E. coli F factor plasmid system and are simple to manipulate
and purify in microgram quantities. Because BAC plasmids are
kept at one to two copies per cell, the problems of
rearrangement observed with YACs, which can also be employed in
the present methods, are reduced. For delivery of bacterial
artificial chromosomes into mammalian cells see, e.g., Baker
(1997) Nucleic Acids Res. 25:1950-1956. BAC vectors can include
marker genes for luciferase and green fluorescent protein (GFP).
(Baker (1997) Nucleic Acids Res 25:1950-1956). P1 is a
bacteriophage that infects E. coli that can contain 75-100 Kb
DNA inserts (Mejia (1997) Genome Res 7:179-186; Ioannou (1994)
Nat Genet 6:84-89), and are screened in much the same way as
lambda libraries.
[0112] iii. Analysis of the
mTERT Species: Isoforms, Alleles, Homologues
[0113] The mTERT-encoding nucleic acid sequences of the
invention include isolated and recombinant nucleic acids
relating to mTERT genes and gene products identified and
characterized by analysis of mTERT sequences. Optimal alignment
of sequences for comparison can use any means to analyze
sequence identity (homology) known in the art, e.g., by the
progressive alignment method of termed "PILEUP" (see below); by
the local homology algorithm of Smith & Waterman, Adv. Appl.
Math. 2: 482 (1981); by the homology alignment algorithm of
Needleman & Wunsch, J. Mol. Biol. 48:443 (1970); by the
search for similarity method of Pearson (1988) Proc. Natl. Acad.
Sci. USA 85: 2444; by computerized implementations of these
algorithms (GAP, BESTFIT, FASTA, and TFASTA in the Wisconsin
Genetics Software Package, Genetics Computer Group, 575 Science
Dr., Madison, Wis.); ClustalW (CLUSTAL in the PC/Gene program by
Intelligenetics, Mountain View, Calif., described by Higgins
(1988) Gene, 73: 237-244; Corpet (1988) Nucleic Acids Res.
16:10881-90; Huang (1992) Computer Applications in the
Biosciences 8:155-65, and Pearson (1994) Methods in Molec. Biol.
24:307-31), TreeAlign, MALIGN, and SAM sequence alignment
computer programs; or, by inspection. See also Morrison (1997)
Mol. Biol. Evol. 14:428-441, as an example of the use of PILEUP.
PILEUP creates a multiple sequence alignment from a group of
related sequences using progressive, pairwise alignments. It can
also plot a tree showing the clustering relationships used to
create the alignment. PILEUP uses a simplification of the
progressive alignment method of Feng & Doolittle, J. Mol.
Evol. 35:351-360 (1987). The method used is similar to the
method described by Higgins & Sharp (1989) CABIOS 5:
151-153. The program can align up to 300 sequences of a maximum
length of 5,000. The multiple alignment procedure begins with
the pairwise alignment of the two most similar sequences,
producing a cluster of two aligned sequences. This cluster can
then be aligned to the next most related sequence or cluster of
aligned sequences. Two clusters of sequences can be aligned by a
simple extension of the pairwise alignment of two individual
sequences. The final alignment is achieved by a series of
progressive, pairwise alignments. The program can also be used
to plot a dendogram or tree representation of clustering
relationships. The program is run by designating specific
sequences and their amino acid or nucleotide coordinates for
regions of sequence comparison. For example, hTERT can be
compared to other TERT species using the following parameters:
default gap weight (3.00), default gap length weight (0.10), and
weighted end gaps.
[0114] Another example of algorithm that is suitable for
determining sequence similarity is the BLAST algorithm, which is
described in Altschul (1990) J. Mol. Biol. 215: 403-410.
Software for performing BLAST analyses is publicly available
through the National Center for Biotechnology Information; see
also Zhang (1997) Genome Res. 7:649-656 (1997) for the
"PowerBLAST" variation. This algorithm involves first
identifying high scoring sequence pairs (HSPs) by identifying
short words of length W in the query sequence that either match
or satisfy some positive-valued threshold score T when aligned
with a word of the same length in a database sequence. T is
referred to as the neighborhood word score threshold (Altschul
et al, supra). These initial neighborhood word hits act as seeds
for initiating searches to find longer HSPs containing them. The
word hits are extended in both directions along each sequence
for as far as the cumulative alignment score can be increased.
Extension of the word hits in each direction are halted when:
the cumulative alignment score falls off by the quantity X from
its maximum achieved value; the cumulative score goes to zero or
below, due to the accumulation of one or more negative-scoring
residue alignments; or the end of either sequence is reached.
The BLAST algorithm parameters W, T, and X determine the
sensitivity and speed of the alignment. The BLAST program uses
as defaults a wordlength (W) of 11, the BLOSUM62 scoring matrix
(see Henikoff (1989) Proc. Natl. Acad. Sci. USA 89:10915)
alignments (B) of 50, expectation (E) of 10, M=5, N=-4, and a
comparison of both strands. The BLAST algorithm performs a
statistical analysis of the similarity between two sequences
(see, e.g., Karlin (1993) Proc. Natl. Acad. Sci. USA 90:
5873-5787). One measure of similarity provided by the BLAST
algorithm is the smallest sum probability (P(N)), which provides
an indication of the probability by which a match between two
nucleotide or amino acid sequences would occur by chance.
[0115] iv. Sequencing of mTERT
DNA
[0116] Sequencing of isolated mTERT-encoding nucleic acid can be
used to identify and characterize new mTERT species. mTERT
protein-encoding sequences can be sequenced as inserts in
vectors, as inserts released and isolated from the vectors or in
any of a variety of other forms (i.e., as amplification
products). mTERT-encoding inserts can be released from the
vectors by restriction enzymes or amplified by PCR or
transcribed by a polymerase. For sequencing of the inserts to
identify full length mTERT coding sequences, primers based on
the N- or C-terminus, or based on insertion points in the
original phage or other vector, can be used. Additional primers
can be synthesized to provide overlapping sequences. A variety
of nucleic acid sequencing techniques are well known and
described in the scientific and patent literature, e.g., see
Rosenthal (1987) supra; Arlinghaus (1997) Anal. Chem.
69:3747-3753, for use of biosensor chips for sequencing; Healey
(1997) Anal. Biochem. 251:270-279, describing fiberoptic DNA
sensor arrays capable of detecting point mutations; Pastinen
(1996) Clin. Chem. 42:1391-1397; Nyren (1993) Anal Biochem.
208:171-175.[0117] v. Chromosomal Location of mTERT Encoding DNA
[0118] Identification of the location of the chromosomal
location of mTERT coding sequences in different strains of
wild-type mice will provide insights into mechanisms controlling
the expression of the mTERT gene. Identification of the
chromosomal location of mTERT in transgenic and mouse mTERT
"knockout" mice also helps evaluate model systems. To ascertain
the chromosomal location of the mTERT gene in a mouse, the
segregation of mTERT in a Jackson Laboratory BSS interspecific
backcross (see Rowe (1994) Mammalian Genome 5:253-274) was
analyzed. Comparison of the allele distribution pattern of the
mTERT locus with those of other loci previously mapped
throughout the genome showed that mTERT cosegregated with
D13Mit8 and D13Gor1 (Rowe (1994) supra, Xu (1996) Mammalian
Genome 7:16-19). Comparing the BSS cross data to information
from other linkage crosses in the Mouse Genome Database (MGD,
see www.informatics.jax.org/mgd.html, The Jackson Laboratory),
one finds that mTERT fits the composite mouse chromosome 13 map
near MGD offset 40, in proximity to srd5a1, Adcy2, Dat1, and
S1c9a3 genes. The specific region to which mTERT maps defines a
conserved linkage group near the terminus of the short arm of
human chromosome 5, band 15. Similar techniques can be used to
map mTERT inserted into transgenic animals into which mTERT
nucleic acid has been inserted to express murine telomerase as
an exogenous entity; or, in "knockout" mice into which mTERT
nucleic acid or a variant has been inserted to alter or abrogate
the expression of endogenous mTERT.
[0119] c. Nucleic Acid
Hybridization Techniques
[0120] The hybridization techniques disclosed herein can be
utilized to identify, isolate and characterize genes and gene
products (i.e., mRNA) encoding mTERT species. A variety of
methods for specific DNA and RNA detection and measurement using
nucleic acid hybridization techniques are known to those of
skill in the art. See, e.g., NUCLEIC ACID HYBRIDIZATION, A
PRACTICAL APPROACH, Ed. Hames, B. D. and Higgins, S. J., IRL
Press, 1985; Gall (1989) Proc. Natl. Acad. Sci. USA 63:378; and
Sambrook. The selection of a DNA hybridization format is often
optional. For example, one method for evaluating the presence or
absence of a DNA encoding an mTERT protein in a sample involves
a Southern transfer. Briefly, the nucleic acid sample, such as
digested murine DNA or mRNA, is run on agarose slab or
polyacrylamide gel in buffer and transferred to membranes.
Hybridization is carried out using nucleic acid probes. For the
mTERT nucleic acids of this invention, the nucleic acid probes
can comprise nucleic acid sequences conserved amongst mTERT
nucleic acids. Preferably nucleic acid probes are 10 to 20 bases
or longer in length, see, e.g., Sambrook for methods of
selecting nucleic acid probe sequences for use in nucleic acid
hybridization. Both quantitative and qualitative determination
of the presence or absence of DNA or RNA encoding mTERT protein
can be performed in accordance with the present methods.
[0121] Similarly, and as but one of many examples, a Northern
transfer can be used for the detection of murine message RNA
encoding mTERT polypeptides. For example, mRNA is isolated from
a given cell sample using an acid guanidinium-phenol-chloroform
extraction method. The mRNA is then electrophoresed to separate
the mRNA species and the mRNA is transferred from the gel to a
nitrocellulose membrane. As with the Southern transfers, probes,
labeled probes or PCR amplification products can be used to
identify the presence or absence of telomerase protein-encoding
nucleic acid. The mTERT mRNA of the invention is often expressed
in cells at such low levels that it can be difficult to detect
by Northern blotting, even using the most sensitive assays. This
can be true even with cells that express relatively high levels
of mTERT mRNA, such as indefinitely proliferating, immortal and
cancer cells. The low level of mTERT mRNA, even in
mTERT-positive cells, ie., cells that express telomerase enzyme
activity, such as cancer cells, is reflected by the low levels
of mTERT protein that may be seen in such cells. Such protein
can be detected by the detection methods of the invention,
including immunoblotting (e.g., Western blots).
[0122] Sandwich assays can also be used to detect mTERT species.
They are commercially useful hybridization assays for detecting
or isolating protein or nucleic acid. Such assays utilize a
"capture" nucleic
acid or protein that is often covalently immobilized to a solid
support and a labeled "signal" nucleic acid, typically in
solution. A clinical or other sample provides the target nucleic
acid or protein. The "capture" nucleic acid or protein and
"signal" nucleic acid or protein hybridize with or bind to the
target nucleic acid or protein to form a "sandwich"
hybridization complex. To be effective, the signal nucleic acid
or protein cannot hybridize or bind substantially with the
capture nucleic acid or protein. Typically, oligonucleotide
probes are labeled signal nucleic acids that are used to detect
hybridization. Complementary probe nucleic acids or signal
nucleic acids may be labeled by any one of several methods
typically used to detect the presence of hybridized
polynucleotides. Labels for autoradiography or autofluorography,
such as <3> H, <125> I, <35> S, <14> C,
or <3> P-labeled probes or the like (see definition of
label, above) can be used. Other labels include ligands which
bind to labeled antibodies, fluorophores, chemiluminescent
agents, enzymes, and antibodies which can serve as specific
binding pair members for a labeled ligand.
[0123] Detection of a hybridization complex may require the
binding of a signal generating complex to a duplex of target and
probe polynucleotides or nucleic acids. Typically, such binding
occurs through ligand and anti-ligand interactions as between a
ligand-conjugated probe and an anti-ligand conjugated with a
signal, i.e., antibody-antigen or complementary nucleic acid
binding. The label may also allow indirect detection of the
hybridization complex. For example, where the label is a hapten
or antigen, the sample can be detected by using antibodies. In
these systems, a signal is generated by attaching fluorescent or
enzymatic molecules to the antibodies or, in some cases, by
attachment of a radioactive label. The sensitivity of the
hybridization assays may be enhanced through use of a target
nucleic acid or signal amplification system which multiplies the
target nucleic acid or signal being detected. In vitro
amplification techniques suitable for amplifying sequences for
use as molecular probes or for generating nucleic acid fragments
for subsequent subcloning are known, as described above. These
systems can be used to directly identify allelic variations or
mutated sequences where the PCR or LCR primers or other reagents
are designed to be extended or ligated only when a specific
sequence is present. Alternatively, the specific sequences can
be generally amplified using, for example, more generic PCR
primers and the amplified target region later probed or
sequenced to identify a specific sequence indicative of the
allele or mutation.
[0124] It will be appreciated that nucleic acid hybridization
assays for identification, diagnosis, sequencing, and the like,
of mTERT can also be performed in an array-based format. Arrays
involve a multiplicity of different "probe" or "target" nucleic
acids (or other compounds) that are hybridized against a target
nucleic acid. In this manner a large number of different
hybridization reactions can be run essentially "in parallel".
This provides rapid, essentially simultaneous, evaluation of a
wide number of reactants. Methods of performing hybridization
reactions in array based formats are well known to those of
skill in the art, e.g., Jackson (1996) Nature Biotechnology
14:1685; Chee, Science 274:610 (1995); Pastinen (1997) Genome
Res. 7:606-614, describing minisequencing on oligonucleotide
arrays; and Drobyshev (1997) Gene 188:45-52, for sequence
analysis by hybridization with oligonucleotide microchip.
[0125] An alternative means for determining the level of
expression of a gene encoding a protein is in situ
hybridization. In situ hybridization assays are well known and
are generally described in Angerer (1987) Methods Enzymol
152:649. In an in situ hybridization assay, cells can be fixed
to a solid support, typically a glass slide, or be free in
solution. If DNA is to be probed, the cells are typically
denatured with heat or alkali. The cells are then contacted with
a hybridization solution at a moderate temperature to permit
annealing of labeled probes specific to the nucleic acid
sequence encoding the protein. The probes are typically labeled,
i.e., with radioisotopes or fluorescent reporters. See also U.S.
Pat. No. 5,583,016, U.S. Ser. Nos. 08/472,802 and 08/482,115,
both filed Jun. 7, 1995; U.S. Ser. No. 08/521,634, filed Aug.
31, 1995; U.S. Ser. No. 08/714,482, filed Sep. 16, 1996; and
U.S. Ser. Nos. 08/770,564 and 08/770,565, both filed 20 Dec.
1996; Soder (1997) Oncogene 14:1013-1021, all of which describe
in situ hybridization of hTERC. Another well-known in situ
hybridization technique is the so-called FISH fluorescence in
situ hybridization, see Macechko (1997) J. Histochem. Cytochem.
45:359-363; and Raap (1995) Hum. Mol. Genet. 4:529-534.
[0126] d. Expression of
Recombinant Telomerase and mTERT
[0127] To create cell-based assay systems to screen for
modulators of mTERT, a variety of cell-based and in vitro
systems are provided by the invention. The invention provides
for methods and reagents to express the novel mouse telomerase
enzymes and mTERTs of the invention in any prokaryotic,
eukaryotic, yeast, fungal, plant, insect, human or animal cell,
either alone or co-expressed with a telomerase-associated RNA
moiety and/or other telomerase-associated proteins. The mTERT
can be associated with mTERC or hTERC. The transfected mTERT can
be expressed as an exogenous telomerase in a cell having full or
partial endogenous telomerase enzyme activity. The mTERT can
also be mutated or modified and subsequently transfected and
expressed in a mouse cell.
[0128] In one embodiment, the endogenous mTERT can be first
debilitated, or "knocked out" in either one or both alleles
before introducing an exogenous TERT and/or TERC (e.g., altering
endogenous mTERT activity and reconstituting with mTERT and
mTERC, mTERT and hTERC, hTERT and mTERC, or, hTERT and hTERC)
and other telomerase-associated components. The expression of
mTERT in cells that have less than full or completely "knocked
out" endogenous telomerase activity can reconstitute or
re-introduce full or partial telomerase enzyme activity. Other
telomerase-associated compositions, such as p80, can be
co-expressed in these cell systems.
[0129] Using these or other in vitro or in vivo cell systems,
the invention provides a means to assay for modulators of
telomerase enzyme expression, including agonist and antagonists
of telomerase enzyme and mTERT activity, transcription and
translation of the mTERT gene, and assembly, processivity and
substrate binding of mTERT and telomerase (see the further
discussion of "partial" TERT activity, below). The invention
also provides method for reconstitution of full or partial
telomerase of mTERT activity in vitro.
[0130] Telomerase-encoding nucleic acids of the invention may be
introduced into the genome or into the cytoplasm or nucleus of
an animal or plant cell by a variety of conventional techniques,
well described in the scientific and patent literature. A few
selected illustrative general and specific teaching examples
relevant to such technology are described below.
[0131] i. Cloning, Vectors, and
Transcriptional Control Elements
[0132] The invention provides methods and reagents for
expressing the novel murine telomerase enzyme and mTERT nucleic
acids of the invention and further provides methods and reagents
for identifying, isolating and using mTERT transcriptional and
translational cis- and trans-acting control elements. After the
coding region of a mTERT gene has been identified, the
expression of natural, recombinant or synthetic mTERT-encoding
or other (i.e., antisense, ribozyme) mTERT nucleic acids can be
achieved by operably linking the coding region to a promoter
(that can be telomerase-specific or not, constitutive or
inducible), incorporating the construct into an expression
vector, and introducing the vector (or plasmid) into a suitable
host cell. Synthetic procedures may also be used. Typical
vectors contain transcription and translation terminators,
transcription and translation initiation sequences, and
promoters useful for transcribing DNA into RNA.
[0133] The vectors optionally comprise generic expression
cassettes containing at least one independent terminator
sequence, sequences permitting replication of the cassette in
eukaryotes, or prokaryotes, or both (e.g., shuttle vectors), and
selection markers for both prokaryotic and eukaryotic systems.
See, for example Roberts, Nature (1987) 328:731; Berger (1987)
supra; Schneider (1995) Protein Expr. Purif. 6435:10; Sambrook
and Ausubel. Product information from manufacturers of
biological reagents and experimental equipment also provide
information regarding known biological methods. Such
manufacturers include the SIGMA chemical company (Saint Louis,
Mo.), R&D systems (Minneapolis, Minn.), Pharmacia Biotech
(Piscataway, N.J.), Clontech Laboratories, Inc. (Palo Alto,
Calif.), Aldrich Chemical Company (Milwaukee, Wis.), GIBCO BRL
Life Technologies, Inc. (Gaithersburg, Md.), Fluka
Chemica-Biochemika Analytika (Fluka Chemie AG, Buchs,
Switzerland), Applied Biosystems (Foster City, Calif.), as well
as many other commercial sources known to one of skill.
Promoters and vectors useful in regards in this invention can
also be isolated from natural sources, obtained from such
sources as the ATCC or from GenBank libraries, or prepared by
synthetic methods, as described herein.
[0134] Various embodiments of the invention include use of
inducible and constitutive promoters, depending on the
expression system and desired levels of control of expressed
protein. For example, the Tet-On/Tet-Off systems available from
Clontech are useful in this regard. Viral, prokaryotic or
eukaryotic promoters can be incorporated in expression vectors
or expression cassettes. For example, highly efficient viral
promoters can be used in the expression vectors of the
invention, including cytomegalovirus (CMV) immediate early
promoter, Rous sarcoma virus (RSV), murine leukemia virus
(SL3-3) and simian virus 40 (SV40) early promoters. Other viral
sequences, such as adenovirus tripartite leader (TPL) sequences,
can also increase expression yields in eukaryotic expression
systems (see, e.g., Lee (1997) Mol. Cells 7:495-501).
[0135] The telomerase enzyme and mTERT of the invention can be
expressed in vectors which are transiently expressed in cells
using, e.g., episomal vectors such as those derived from
vaccinia virus, see Cooper (1997) Proc Natl Acad Sci USA
94:6450-6455; Muruve (1997) Transplantation 64:542-546.
Alternatively, mTERT coding sequences can be inserted into the
host cell genome becoming an integral part of the host
chromosomal DNA, using for example, retroviral vectors derived
from, e.g., SIV or HIV, see, e.g. Naldini (1996) Science
272:263-267; Vanin (1997) J. Virol. 71:7820-7826; Zufferey
(1997) Nat. Biotechnol. 15:871-875, describing attenuated
lentiviral vector gene delivery in vivo; Feng (1997) Nat
Biotechnol 15:866-870, describing stable in vivo gene
transduction via adenoviral/retroviral chimeric vector.
[0136] Expression vectors can contain selection markers that
confer a selectable phenotype on transformed cells and sequences
coding for episomal maintenance and replication such that
integration into the host genome is not required. For example,
the marker may encode antibiotic resistance, particularly
resistance to chloramphenicol, kanamycin, G418, bleomycin and
hygromycin, to permit selection of those cells transformed with
the desired DNA sequences, see, e.g., Blondelet-Rouault (1997)
Gene 190:315-317; Aubrecht (1997) J. Pharmacol. Exp. Ther.
281:992-997. Because selectable marker genes conferring
resistance to substrates like neomycin or hygromycin can in
certain cases only be utilized in tissue culture,
chemoresistance genes are also used as selectable markers in
vitro and in vivo. Various target cells are rendered resistant
to anticancer drugs by transfer of chemoresistance genes
encoding P-glycoprotein, multidrug resistance-associated
protein-transporter, dihydrofolate reductase,
glutathione-S-transferase, O 6-alkylguanine DNA
alkyltransferase, or aldehyde reductase (Licht (1997) Stem Cells
15:104-111), and the like.
[0137] A DNA or RNA sequence coding for an mTERT protein, e.g.,
a cDNA sequence encoding the full length mTERT, can be combined
with transcriptional (such as promoters and enhancers) and
translational regulatory sequences which will direct the
transcription and translation of the nucleic acid in a
constitutive or a cell-specific or tissue-specific manner. A
wide variety of well known transcriptional regulatory elements
can be included in the vectors selected to express an mTERT
protein of the invention. mTERT promoter constructs which direct
the expression of mTERT in its native state are provided by the
invention. Additional mTERT promoters can be identified by
analyzing the 5' sequences of murine genomic clones. Sequences
controlling eukaryotic gene expression have been extensively
studied, and promoters have characteristic subsequences. For
instance, promoter sequence elements include the TATA box
consensus sequence (TATAAT), which is usually 20 to 30 base
pairs upstream of the transcription start site. In most
instances, the TATA box is required for accurate transcription
initiation. In construction of recombinant expression cassettes
of the invention, a recombinant or isolated promoter fragment,
either related to the murine telomerase of this invention or
heterologous thereto, may be employed which will direct
expression of the gene in all or only some of the tissues of a
transgenic organism, depending on the promoter and conditions
employed. Promoters that drive expression continuously under
physiological conditions, ie., "constitutive" promoters, are
active under most environmental conditions and states of
development or cell differentiation.
[0138] In some expression systems, to ensure optimal polypeptide
expression levels, a polyadenylation region at the 3'-end of the
coding region can be included. The polyadenylation region can be
derived from the natural gene or from any of a variety of other
genes, e.g., see de Moor (1997) Mol. Cell. Biol. 17:6419-6426.
[0139] ii. Transformation of
Cells with mTERT-vectors
[0140] There are several well-known methods of introducing
nucleic acids into bacterial and other cells, a process often
called "transforming," any of which may be used in the methods
of the present invention (see Sambrook). Techniques for
transforming a wide variety of animal and plant cells are well
known and described in the technical and scientific literature.
See, e.g., Weising (1988) Ann. Rev. Genet. 22:421-477, for plant
cells and Sambrook for animal and bacterial cells. Specific
examples of methods of expressing the novel murine telomerase
proteins of the invention are described below. For example,
these include fusion of the recipient cells with bacterial
protoplasts containing mTERT DNA, DEAE dextran transformation,
infection with viral vectors, and the like.
[0141] Methods for transforming bacterial cells are well known
in the art, and include, e.g., electroporation and heat shock of
competent cells (see, e.g., Sambrook). Bacterial strains which
can be used to express telomerase nucleic acid include, e.g.,
Escherichia coli, Bacillus subtillus, Streptococcus cremoris,
Streptococcus lactis, Streptococcus thermophilus, Leuconostoc
citrovorum, Leuconostoc mesenteroides, Lactobacillus
acidophilus, Lactobacillus lactis, Bifidobacterium bifidum,
Bifidobacteriu breve, and Bifidobacterium longum. To simplify
identification of colonies of bacteria transformed with vectors
containing the inserts, many cloning vectors have restriction
enzyme sites or other splicing sites located within a coding
sequence for an enzyme, such as, e.g., beta-galactosidase. If an
insert has successfully been inserted into the vector at the
restriction or splicing sites, the enzyme is either activated or
inactivated. After transformation of the bacteria with the
vector, colonies grown in the presence of
isopropyl-D-thiogalactoside (IPTG) (for beta-galactosidase)
appear white, while the colonies derived from a bacteria which
did not incorporate the insert appear blue in the presence of
the substrate. Thus, even if the frequency of ligation of the
insert into the vector was low, one can pick the few colonies
that contain inserts over the many that do not.
[0142] In addition to bacterial expression systems, the TERT and
telomerase-associated proteins of this invention can be
expressed in other systems, such as yeast, insect (baculovirus),
mammalian and plant cells. The system used will depend on a
variety of factors, including activities and amounts desired.
[0143] Yeast expression systems, being eukaryotic, provide an
attractive alternative to bacterial systems for some
applications; for an overview of yeast expression systems, see
Protein Engineering Principles and Practice, eds. Cleland et
al., Wiley-Liss, Inc. p 129 (1996). A variety of yeast vectors
are publicly available. For example, the expression vector pPICZ
B (Invitrogen, San Diego, Calif.) has been modified to create
expression vectors of the invention to express the mTERT of the
invention in yeast, such as Pichia pastoris. Yeast episomal
plasmids comprising inducible promoters can be used for the
intracellular expression of protein. Vectors include the pYES2
expression vector (Invitrogen, San Diego, Calif.) and pBS24.1
(Boeke (1984) Mol. Gen. Genet. 197:345); see also Jacobs (1988)
Gene 67:259-269. Yeast promoters for yeast expression vectors
suitable for the expression of an mTERT include the inducible
promoter from the alcohol dehydrogenase gene, ADH2, also called
the yeast alcohol dehydrogenase II gene promoter (ADH2P) (La
Grange (1997) Appl. Microbiol. Biotechnol. 47:262-266). In
another embodiment, the TERT to be expressed can also be fused
at the amino terminal end to the secretion signal sequence of
the yeast mating pheromone alpha-factor (MF alpha 1S) and fused
at the carboxy terminal end to the alcohol dehydrogenase II gene
terminator (ADH2T), see van Rensburg (1997) J. Biotechnol.
55:43-53. The yeast alpha mating pheromone signal sequence
allows for secretion of the expressed telomerase. Direct
intracellular expression of mTERT is useful for a variety of
cell-based screens or mTERT protein production or telomerase
enzyme reconstitution.
[0144] Yeast strains which can be used to express exogenous
nucleic acids include Pichia pastoris, Hansenula polymorpha,
Torulopsis holmil, Saccharomyces fragilis, Saccharomyces
cerevisiae, Saccharomyces lactis, and Candida pseudotropicalis.
A large number of vectors are available for S. cerevisiae.
Kluyveromyces lactis and the methylotrophs Hansenula polymorphas
and Pichia pastoris can offer certain advantages over baker's
yeast S. cerevisiae for the production of certain proteins, see
Gellissen (1997) Gene 190:87-97; Wegner (1990) FEMS Microbiol.
Rev. 87:279.
[0145] The present invention also provides insect expression
systems to express large amounts of recombinant mTERT and
telomerase enzyme of the invention. A commonly used insect
system utilizes Spodoptera frugiperda infected with a
baculovirus, such as Autographa californica nuclear polyhedrosis
virus. This virus can be used to infect Sf21 (Deutschmann (1994)
Enzyme Microb Technol 16:506-512) or Sf9 cells (MaxBac 2.0,
Invitrogen, San Diego, Calif.) (Zhu (1996) J. Virol. Methods
62:71-79) derived from Spodoptera frugiperda, High Five cells
derived from Trichoplusia ni insect cells (Parrington (1997)
Virus Genes 14:63-72), and Lymantria dispar (Vaughn (1997) In
Vitro Cell Dev Biol Anim 33:479-482); see also Grabherr (1997)
Biotechniques 22:730-735). Baculovirus transfer vectors can be
used to replace the wild-type AcMNPV polyhedron gene with a
heterologous gene of interest. Sequences that flank the
polyhedrin gene in the wild-type genome are positioned 5' and 3'
of the expression cassette on the transfer vectors. Following
cotransfection with AcMNPV DNA, a homologous recombination event
occurs between these sequences resulting in a recombinant virus
carrying the gene of interest and the polyhedrin or p10
promoter. Baculovirus expression vectors are publicly available,
such as pAC360 (Invitrogen, San Diego, Calif.). In addition to
manufacturers' instructions accompanying the commercially
available baculovirus systems, see, e.g., "Current Protocols in
Molecular Biology," Ausubel, Chapter 16.
[0146] The present invention also provides methods and reagents
for recombinant mTERT and telomerase enzyme expression in plant
cell systems. Constitutive promoters of plants include the
cauliflower mosaic virus (CaMV) 35S transcription initiation
region, the 1'- or 2'-promoter derived from T-DNA of
Agrobacterium tumafaciens, the promoter of the tobacco mosaic
virus and transcription initiation regions from various plant
genes known to those of skill in the art. The promoter may
direct expression in only a specific tissue (tissue-specific
promoters) or may be under environmental control (inducible
promoters). Examples of tissue-specific plant promoters under
developmental control include promoters that initiate
transcription only in certain tissues, such as fruit, seeds, or
flowers. The tissue specific E8 promoter from tomato is
particularly useful for directing gene expression so that a
desired gene product is located in fruits. Other suitable
promoters include those from genes encoding embryonic storage
proteins. Examples of environmental conditions that may affect
transcription by inducible promoters include anaerobic
conditions, elevated temperature, or the presence of light.
[0147] Plants can be transformed using viral vectors, such as,
for example, tobacco mosaic virus derived vectors, to express
recombinant telomerase enzyme or mTERT of the invention.
Selection and construction of vectors and techniques for
transforming a wide variety of plant cells are well known, e.g.,
see Hamamoto, U.S. Pat. No. 5,618,699. For example, mTERT
constructs can be combined with suitable T-DNA flanking regions
and introduced into a conventional Agrobacterium tumefaciens
host vector. The virulence functions of the Agrobacterium
tumefaciens host will direct the insertion of the construct and
adjacent marker into the plant cell DNA when the cell is
infected by the bacteria. Agrobacterium tumefaciens-mediated
transformation techniques, including disarming and use of binary
vectors, are well described in the scientific literature. See,
e.g., Horsch, Science (1984) 233:496, and Fraley (1983) Proc.
Natl Acad. Sci USA 80:4803; see also Chong (1997) Transgenic
Res. 6:289-296, describing Agrobacterium tumefaciens-mediated
leaf disc transformation methods. Plant regeneration from
cultured protoplasts is described in Evans, PROTOPLASTS
ISOLATION AND CULTURE, HANDBOOK OF PLANT CELL CULTURE, pp.
124-176, Macmillian Publishing Company, New York, 1983; and
Binding, REGENERATION OF PLANTS, PLANT PROTOPLASTS, pp. 21-73,
CRC Press, Boca Raton, 1985. Regeneration can also be obtained
from plant callus, explants, organs, or parts thereof. Such
regeneration techniques are described generally in Klee (1987)
Ann. Rev. of Plant Phys. 38:467; Jafari (1995) Acta Biol. Hung.
46:51-59.
[0148] The invention provides methods and reagents for
expression of mTERT and telomerase enzyme in mortal,
transformed, or transformed immortal indefinitely proliferating
mammalian cells using a wide variety of combinations of
transcriptional control elements (e.g., promoters and
enhancers), translational control elements, vectors (plasmid,
viral, episomal, integrating), selectable marker genes, and
related agents and cells. In some embodiments, endogenous mTERT,
or mTERT and mTERC, activity can be debilitated, modified or
fully deleted, ie., "knocked out," before insertion of vectors
encoding modified endogenous or exogenous TERT (e.g., hTERT),
TERC (e.g., hTERC) or other telomerase enzyme-associated
compositions of the invention. The endogenous mTERT can be
debilitated or deleted in either one or both alleles. The
endogenous mTERC can also be debilitated or deleted in either
one or both alleles. In an alternative embodiment, the mTERT of
the invention or a variant, such as a deletion variant, is
introduced into the cell to produce such a "knock-out" cell or
animal.
[0149] Promoters can be constitutive or inducible, as described
above. Vectors and promoters can be "transcriptionally targeted"
to restrict the expression of the TERT sequence to appropriate
cells. If the expression is to be used in a therapeutic method,
such as gene therapy, there may be a therapeutic window for
certain proteins such that levels of expression below and above
certain thresholds may be ineffective or toxic, requiring
vectors that allow exogenous control of expression, so that
levels of the therapeutic protein can be raised or lowered
according to therapeutic need. See e.g., Miller (1997) Hum. Gene
Ther. 8:803-815; Walther (1996) J. Mol. Med. 74:379-392; Walther
(1997) Gene Ther. 4:544-552.
[0150] In one embodiment of the invention, recombinant mTERT is
expressed in normal, diploid mortal cells to create an
indefinitely proliferating cell or to immortalize them.
Illustrative vectors incorporating mTERT genes and coding
sequences for the production of indefinitely proliferating and
immortal B lymphocytes to obtain cells for monoclonal antibody
production include, e.g., adenovirus-based vectors (Cantwell
(1996) Blood 88:4676-4683; Ohashi (1997) Proc Natl Acad Sci USA
94:1287-1292), Epstein-Barr virus-based vectors (Mazda (1997) J
Immunol Methods 204:143-151), adenovirus-associated virus
vectors, Sindbis virus vectors (Strong (1997) Gene Ther 4:
624-627), Herpes simplex virus vectors (Kennedy (1997) Brain
120:1245-1259) and retroviral vectors (Schubert (1997) Curr Eye
Res 16:656-662). The present invention provides a variety of
vectors for introducing mTERT and telomerase enzyme into cells
to produce an indefinitely proliferating or immortal normal cell
that in turn produces a commercially desirable protein, such as
pituitary cells that make hormones, like growth hormone, and is
karyotypically normal. Epstein-Barr virus episomal vectors
(Horlick (1997) Protein Expr. Purif. 9:301-308), and plasmid DNA
(Lowrie (1997) Vaccine 15: 834-838) can also be used to express
the mTERT and/or the telomerase enzyme of the invention in vivo
or ex vivo. The use of mammalian tissue cell culture to express
polypeptides is discussed generally in Winnacker, From Genes to
Clones, VCH Publishers, NY, N.Y., 1987)
[0151] vii. Optimizing
Expression of mTERT and Telomerase Enzyme
[0152] In bacterial and other expression systems, codon usage is
known to present a potential impediment to high-level gene
expression. "Rare" codons, depending on their frequency and
context in an mRNA, can have an adverse effect on levels of
protein translated therefrom. The problem, if encountered, can
be alleviated by modification of the relevant codons or by
coexpression of the cognate tRNA genes or by other means (see
Kane (1995) Curr. Opin. Biotechnol. 6:494-500). Use of
protease-deficient host strains can also increase yields from
bacterial expression systems, see Makrides (1996) Microbiol Rev
60:512-538.
[0153] One can also optimize levels of expression of mTERT by
vector design modifications, such as using exogenous
transcriptional regulatory elements. For example, as discussed
below, the myeloproliferative sarcoma virus (MPSV) LTR promoter
consistently drives higher expression levels in some mammalian
cell lines (see Dirks (1994) Gene 149:389-390).
[0154] Generally, those of skill in the art recognize that
nucleic acids having certain specific sequences can be poorly
expressed in one cell and expressed well in other cells. Thus,
alternative embodiments of the invention include expression
systems that do not incorporate extraneous sequences, i.e.,
non-coding sequences such as 3' untranslated sequences from a
cDNA, with the desired coding sequence. Thus, one optimization
method involves removing all extraneous sequences from the
coding sequence insert. This method can in some circumstances
increase protein expression 5 to 10 fold in bacteria, insect,
yeast, mammalian and other cells expression systems.
[0155] Gene amplification, whether by higher vector copy number
or by replication of a gene in a chromosome, can increase yields
of recombinant proteins in mammalian and other cells. One
amplification method for heterologous gene expression in
mammalian cells is based on the stable transfection of cells
with long, linear DNA molecules having several copies of
complete expression units coding for the gene of interest linked
to one terminal unit coding for a selectable marker. Gene
amplification of the gene of interest can be achieved by linking
it to a dihydrofolate reductase (Dhfr) gene and administering
methotrexate to the transfected cells; this method can increase
recombinant protein production many fold (see Monaco (1996) Gene
180:145-150).
[0156] vii Use of Cells,
Animals and Plants Expressing Recombinant mTERT
[0157] The invention provides in vivo assays using transformed
cells and transgenic animals expressing recombinant mTERT. These
living assay systems can be used to screen for modulators of
mTERT; the endogenous TERT, or TERT and TERC, in the non-human
cells or animal can be first modified, debilitated, or "knocked
out" before reconstituting telomerase activity with mTERT, or,
mTERT and mTERC. The reconstitution can be with or without the
co-introduction of mTERC or hTERC and/or other telomerase
enzyme-associated components. In one embodiment, the invention
provides screening assays to identify modulators of mTERT and
telomerase enzyme activity in vitro and in vivo, such as in
animal and plant cells and whole organisms. The screening assays
can utilize mTERT or telomerase enzyme derived by a full or
partial reconstitution of telomerase activity, or by an
augmentation of existing activity. The assay or screens provided
by the invention can be used to test for the ability of
telomerase to synthesize telomere DNA or to test for any one or
all or of the "partial activities" of mTERT. The assay can
incorporate ex vivo modification of cells which have been
manipulated to express mTERT with or without an RNA moiety (such
as mTERC or hTERC) or associated proteins, and these can be
reimplanted into an animal, and so used for in vivo testing.
[0158] The invention also provides transformed cells, transgenic
animals and methods for expressing mTERT in such animals, as
well as otherwise normal cells that can be used to express
compositions of interest and can be used in related methods.
Such transformed cells and transgenic animals can express the
exogenous mTERT either alone or co-expressed with an RNA moiety
(i.e., mTERC or hTERC) or other telomerase-associated proteins.
The invention provides transgenic animals and recombinant cells
to be used, e.g., as bioreactors (Khillan (1997) Methods Mol.
Biol. 63:327-342) to produce large amounts of mTERT or
telomerase enzyme.
[0159] The mTERT-expressing nucleic acid of the invention may be
introduced into the genome of an animal or plant host organism
by a variety of conventional techniques (Jacenko (1997) Methods
Mol. Biol. 62:399-424). For example, recent advances in
transgenic and gene-targeting approaches allow a sophisticated
manipulation of the mouse genome by gene addition, gene
deletion, or gene modifications, making this animal convenient
for the methods of the invention (Franz (1997) J. Mol. Med.
75:115-129; Peterson (1997) Genet. Eng. (N.Y.) 19:235-255). Many
cloning vectors for transgene construction are known in the art,
e.g., Yang (1997) Biotechniques 22:1032-1034. There are two
well-established procedures for simple introduction of DNA into
animal genomes, pronuclear DNA injection and transduction using
a retrovirus (Wei (1997) Annu. Rev. Pharmacol. Toxicol.
37:119-141). Microinjection techniques for use in introducing
DNA into animals and plants are known in the art and described
in the scientific and patent literature (e.g., Bartoli (1997)
Mol. Cell. Biochem. 172:103-109). The introduction of DNA
constructs into cells using polyethylene glycol precipitation is
described, e.g., in Paszkowski (1984) EMBO J. 3:2717.
Electroporation techniques are described, e.g., in Fromm (1985)
Proc. Natl. Acad. Sci. USA 82:5824. Ballistic transformation
techniques are described, e.g., in Klein (1987) Nature 327:70;
Zelenin (1997) FEBS Lett 414:319-322.
[0160] The invention also provides transgenic plants and methods
for expressing the TERT and telomerase enzyme compositions of
the invention and screening assays to identify modulators of
telomerase activity in such plants. In plants, the DNA construct
may be introduced directly into the genomic DNA of the plant
cell using techniques such as electroporation and microinjection
of plant cell protoplasts (Schnorf(1991) Transgenic Res.
1:23-30), or the DNA constructs can be introduced directly to
plant tissue using ballistic methods, such as DNA particle
bombardment (Baum (1997) Plant J. 12:463-469). As discussed
above, plant virus vectors such as tobacco mosaic virus
containing the telomerase sequences of the invention can be used
to inoculate a plant (Rouwendal (1997) Plant Mol Biol
33:989-999).
[0161] e. mTERT-deficient
"Knockout" Mouse Cells and Animals
[0162] In one embodiment, the mTERT nucleic acids and reagents
of the invention are used to create mouse cells and animals in
which the endogenous mTERT is deleted, modified, supplemented or
inhibited. One or several units of the endogenous telomerase
enzyme complex, in addition to mTERT, such as mTERC, can also be
deleted, modified, supplemented or inhibited. For example, mTERT
and mTERC can be deleted, modified or inhibited on either one or
both alleles. The cells or animals can be reconstituted with a
wild-type or modified mTERT or an exogenous TERT, including for
example, a TERT from a non-mouse species, such as hTERT. In TERC
knockout cells, a TERC from a non-mouse species, such as hTERC,
can be introduced. Other telomerase enzyme complex associated
molecules can also be introduced into the knockout cell or
animal. Alternative methodologies for constructing knockout
cells or animals and methods of screening and selection, are all
well known in the art; an illustrative example is set forth
below.
[0163] Construction of a "knockout" cell and animal is based on
the premise that the level of expression of a particular gene in
a mammalian cell can be decreased or completely abrogated by
introducing into the genome a new DNA sequence (e.g., an mTERT
or other nucleic acid construct of the invention) that serves to
interrupt some portion of the DNA sequence of the gene to be
suppressed. To prevent expression of functional enzyme, simple
mutations that either alter the reading frame or disrupt the
promoter can be suitable. To upregulate expression, a native
promoter can be substituted with a heterologous promoter that
induces higher levels of transcription. Also, "gene trap
insertion" can be used to disrupt a host gene, and mouse
embryonic stem (ES) cells can be used to produce knockout
transgenic animals, as described herein and, e.g., in Holzschu
(1997) Transgenic Res 6: 97-106.
[0164] The insertion of the exogenous sequence is typically by
homologous recombination between complementary nucleic acid
sequences. Thus, the exogenous sequence, which is typically an
mTERT nucleic acid in this invention, is some portion of the
target (mTERT) gene to be modified, such as exonic, intronic or
transcriptional regulatory sequences, or any genomic sequence
which is able to affect the level of the target gene's
expression; or a combination thereof. The construct can also be
introduced into other (i.e., non-mTERT gene) locations in the
genome. Gene targeting via homologous recombination in
pluripotential embryonic stem cells allows one to modify
precisely the gene of interest.
[0165] The exogenous sequence is typically inserted in a
construct, usually also with a marker gene to aid in the
detection of the knockout construct and/or a selection gene. The
construct can be any of a variety of expression vectors,
plasmids, and the like, as described above. The knockout
construct is inserted in a cell, typically an embryonic stem
(ES) cell, using a variety of techniques, as described above.
The insertion of the exogenous DNA usually occurs by homologous
recombination. The resultant transformed cell can be a single
gene knockout (i.e., only one of the two copies of the
endogenous mTERT has been modified) or a double gene knockout.
The knockout construct can be integrated into one or several
locations in the cell's genome due to the random nature of
homologous recombination events; however, the recombination does
occur between regions of sequence complementarity. Typically,
less than one to five percent of the ES cells that take up the
knockout construct will actually integrate exogenous DNA in
these regions of complementarity; thus, identification and
selection of cells with the desired phenotype is usually
necessary and a selection or marker sequence is usually
incorporated into the construct for this purpose. Cells which
have incorporated the construct are selected for prior to
inserting the genetically manipulated cell into a developing
embryo; for example, the cells are subjected to positive
selection (using G418, for example, to select for
neomycin-resistance) and negative selection (using, for example,
FIAU to exclude cells lacking thymidine kinase). A variety of
selection and marker techniques are well known in the art, e.g.,
antibiotic resistance selection or beta-galactosidase marker
expression can be used and are further described herein.
Alternatively, insertion of the exogenous sequence and levels of
expression of the endogenous mTERT or marker/selection genes can
be detected by hybridization or amplification techniques or by
antibody-based assays, as described herein.
[0166] After selection of manipulated cells with the desired
phenotype, i.e., complete or partial inability to express mTERT,
the cells are inserted into a mouse embryo. Insertion can be
accomplished by a variety of techniques, such as microinjection,
in which about 10 to 30 cells are collected into a micropipet
and injected into embryos that are at the proper stage of
development to integrate the ES cell into the developing
embryonic blastocyst, at about the eight cell stage, which for
mice is about 3.5 days after fertilization. The embryos are
obtained by perfusing the uterus of pregnant females. After the
ES cell has been introduced into the embryo, it is implanted
into the uterus of a pseudopregnant foster mother, which is
typically prepared by mating with vascectomized males of the
same species. In mice, the optimal time to implant is about two
to three days pseudopregnant. Offspring are screened for
integration of the mTERT nucleic acid sequences and the modified
telomerase activity phenotype. Offspring that have the desired
phenotype are crossed to each other to generate a homozygous
knockout. If it is unclear whether germline cells of the
offspring have modified mTERT, they can be crossed with a
parental or other strain and the offspring screened for
heterozygosity of the desired trait. The heterozygotes can be
crossed with each other to produce mice homozygous for modified
mTERT genomic sequence. While the above described methodology
describes a typical protocol, any technique can be used to
create, screen for, propagate, mTERT knockout mice, e.g., see
Bijvoet (1998) Hum. Mol. Genet. 7:53-62; Moreadith (1997) J.
Mol. Med. 75:208-216; Tojo (1995) Cytotechnology 19:161-165;
Mudgett (1995) Methods Mol. Biol. 48:167-184; Longo (1997)
Transgenic Res. 6:321-328; U.S. Pat. Nos. 5,616,491 (Mak, et
al.); 5,464,764; 5,631,153; 5,487,992; 5,627,059; 5,272,071;
and, WO 91/09955, WO 93/09222, WO 96/29411, WO 95/31560, and WO
91/12650. Thus, the invention provides for the use of the mTERT
reagents of the invention to produce "knockout" mouse cells and
animals, and their progeny, in which one or several units of the
endogenous telomerase enzyme complex have been deleted, modified
or inhibited. These cells and animals can be further
reconstituted with wild type or modified endogenous mTERT or
exogenous TERT, such as hTERT, or other telomerase enzyme
associated components, as described herein.
[0167] f. Site-specific
Mutations
[0168] The invention also provides for an mTERT and telomerase
enzyme that have been modified in a site-specific manner to
modify or delete any or all functions of the telomerase enzyme
or the mTERT protein. Such a modified telomerase provides for
means to alter, especially inhibit, telomerase activity in cells
and animals and so to control the unlimited proliferative
capacity of cells, such as cancer cells. Such telomerases and
mTERT proteins can also be employed in the screens of the
invention to discover therapeutic agents. For example, the mTERT
can be engineered to lose its ability to bind substrate DNA, to
bind an RNA moiety (as mTERC or hTERC), to catalyze the addition
of telomeric DNA, to bind deoxynucleotide substrate, to have
nucleolytic activity, to bind telomere-associated proteins or
chromosomal structures, and the like. The resulting "mutant
proteins" or "muteins" can be used to identify compounds that
specifically modulate one, several, or all functions or
activities of the mTERT protein or telomerase enzyme.
Site-specific mutations can be introduced into mTERT-encoding
nucleic acid by a variety of conventional techniques, well
described in the scientific and patent literature. For example,
one rapid method to perform site-directed mutagenesis
efficiently is the overlap extension polymerase chain reaction
(OE-PCR) (Urban (1997) Nucleic Acids Res. 25:2227-2228). Other
illustrative examples include: Ke (1997) Nucleic Acids Res
25:3371-3372, and Chattopadhyay (1997) Biotechniques
22:1054-1056, describing PCR-based site-directed mutagenesis
"megaprimer" method; Bohnsack (1997) Mol. Biotechnol. 7:181-188;
Ailenberg (1997) Biotechniques 22:624-626, describing
site-directed mutagenesis using a PCR-based staggered
re-annealing method without restriction enzymes; Nicolas (1997)
Biotechniques 22:430-434, site-directed mutagenesis using long
primer-unique site elimination and exonuclease III.
[0169] In another system, a correctly folded, complete protein
and its mutagenized encoding mRNA both remain attached to a
ribosome and can be assessed for alterations in ligand-binding
properties of the native protein. Libraries of native folded
proteins with engineered site-specific mutations can now be
screened while "evolving" in a cell-free system without the
transformation or other constraints imposed when using a host
cell (Hanes (1997) Proc. Natl. Acad. Sci. USA 94:4937-4942).
Modified mTERT proteins of the invention can be produced by
site-directed mutagenesis and/or chemical modification methods
to introduce unnatural amino acid side chains (see Paetzel
(1997) J. Biol. Chem. 272:9994-10003 for general methodology).
[0170] For example, the invention provides for an mTERT protein
that is modified in a site-specific manner and optionally
modified to facilitate cloning into bacterial, mammalian, yeast
and/or insect expression vectors without any 5' and/or 3'
untranslated mTERT sequence, or optionally with altered codon
usage produced synthetically. In some circumstances, minimizing
the amount of non-protein encoding sequence allows for improved
protein production (yield) and/or increase mRNA stability.
[0171] As an illustrative example, one can place an additional
restriction endonuclease site just upstream (5') to the start
(ATG) codon of mTERT cDNA in accordance with the teaching
herein. The creation of a restriction site just 5' to the coding
region for the protein allows for ready construction of a wide
variety of vectors for the production of fusion proteins,
including fusion labels and peptides capable of being bound by
predefined antibodies (TAGs), i.e., for immuno- or other
detection and purification schemes. This modified mTERT provided
by the invention can be conveniently used for the construction
of expression plasmids of the invention.
2. Detection and Purification
of mTERT
[0172] a. Detection of mTERT
and Telomerase Enzyme
[0173] The invention also provides methods and reagents for
detecting or quantitating telomerase enzyme and/or mTERT by a
variety of methods. For example, mTERT can be detected and
quantified by incorporating functional activity assays of the
invention, by immunological assays utilizing a variety of
anti-mTERT antibodies provided by the invention, and by nucleic
acid-based methodologies, examples of which are also described
in detail below.
[0174] i. Antibody Production
[0175] In one embodiment, the invention provides antibodies that
bind one mTERT specie specifically or mTERTs generally, and so
can be used to identify and isolate any mTERT species provided
for in the invention or to identify a single allele, homologue
or isoform of mTERT. Antibodies which can identify any mTERT
specie can be generated by using as antigens peptides containing
structural features, i.e., motifs, common to all mTERT species,
as described herein. In general, the antibodies of the invention
can be used to identify, purify, or inhibit any or all activity
of murine telomerase enzyme complex and mTERT protein.
[0176] Antibodies can act as antagonists of telomerase enzyme
activity in a variety of ways, for example, by preventing the
telomerase complex or nucleotide from binding to its DNA
substrates, by preventing the components of telomerase enzyme
from forming an active complex, by maintaining a functional
(telomerase enzyme complex) quaternary structure or by binding
to one of the enzyme's active sites or other sites that have
allosteric effects on activity (the different partial activities
of telomerase are described in detail elsewhere in this
specification). General methods for producing the antibodies of
the invention are described below.
[0177] Methods of producing polyclonal and monoclonal antibodies
are known to those of skill in the art and described in the
scientific and patent literature, see, e.g., Coligan, CURRENT
PROTOCOLS IN IMMUNOLOGY, Wiley/Greene, N.Y. (1991); Stites
(eds.) BASIC AND CLINICAL IMMUNOLOGY (7th ed.) Lange Medical
Publications, Los Altos, Calif., and references cited therein
("Stites"); Goding, MONOCLONAL ANTIBODIES: PRINCIPLES AND
PRACTICE (2d ed.) Academic Press, New York, N.Y. (1986); Kohler
(1975) Nature 256:495; Harlow and Lane (1988) ANTIBODIES, A
LABORATORY MANUAL, Cold Spring Harbor Publications, New York.
Such techniques include selection of antibodies from libraries
of recombinant antibodies displayed in phage ("phage display
libraries") or similar on cells. See, Huse (1989) Science
246:1275; Ward (1989) Nature 341:544; Hoogenboom (1997) Trends
Biotechnol. 15:62-70; Katz (1997) Annu. Rev. Biophys. Biomol.
Struct. 26:27-45. Recombinant antibodies can be expressed by
transient or stable expression vectors in mammalian cells, as in
Norderhaug (1997) J. Immunol Methods 204:77-87; or in yeast,
Boder (1997) Nat. Biotechnol. 15:553-557.
[0178] To produce large amounts of antibodies for use in, for
example, immunoaffinity purification or diagnostics, a number of
immunogens provided by the invention may be used. Telomerase
enzyme or mTERT isolated or purified from a natural source (see
co-pending U.S. Ser. No. 08/833,377, filed Apr. 4, 1997), from a
recombinant protein isolated from transformed cells provided by
the present invention, or isolated as a synthetically produced
composition, can be used as immunogens for the production of
monoclonal or polyclonal antibodies. Naturally occurring murine
telomerase enzyme or mTERT proteins or recombinant mTERT and/or
telomerase enzyme can be used either in pure or impure form.
Synthetic peptides are made using any portion of the mTERT amino
acid sequence for use as immunogens, particularly peptides
comprising the motif structures described herein. The peptides
can be used alone or conjugated to another composition as
immunogens.
[0179] Methods for the production of polyclonal and monoclonal
antibodies are known to those of skill in the art. In brief, an
immunogen is mixed with an adjuvant, as described above, and
animals are immunized. The animal's immune response to the
immunogen preparation is monitored by taking test bleeds and
determining the titer of reactivity to the immunogen. When
appropriately high titers of antibody to the inununogen are
obtained, blood is collected from the animal and antisera
prepared. Further fractionation of the antisera to enrich for
antibodies reactive to the protein can be done (Harlow and Lane,
supra). Various illustrative peptides, proteins and fusion
proteins of the invention can be used to generate such
polyclonal antibodies.
[0180] Large amounts of monoclonal antibodies for use in
immunoaffinity purification or immunoassays may be obtained by
various techniques familiar to those skilled in the art.
Briefly, spleen cells from an immunized animal are immortalized,
commonly by fusion with a myeloma cell. Alternative methods of
immortalization include transformation with Epstein Barr Virus,
oncogenes, or retroviruses, or other methods well known in the
art. In the antibody-generating methods of the instant
invention, colonies arising from single immortalized cells are
screened for production of antibodies of the desired specificity
and affinity for murine telomerase enzyme and/or mTERT protein.
The yield of the monoclonal antibodies produced by such cells
may be enhanced by various techniques, including injection into
the peritoneal cavity of a vertebrate host. Alternatively, one
may isolate DNA sequences which encode a monoclonal antibody or
a binding fragment thereof by screening a DNA library from
appropriate human B cells, ie., immunized according to the
general protocol outlined in Huse (1989) Science, supra.
[0181] The concentration of telomerase enzyme or mTERT protein
can be measured by a variety of immunoassay methods of the
invention. Generally, immunoassays are described in Stites,
supra. The immunoassays of the present invention can be
performed in any of several configurations; for background
information see ENZYME IMMUNOASSAY, Maggio, ed., CRC Press, Boca
Raton, Fla. (1980); Tijssen, Harlow and Lane, supra.
[0182] To make the anti-mTERT sera of the invention (e.g., for
use in an immunoassay for telomerase) natural, recombinant or
synthetic mTERT or telomerase protein preparations, or
immunogenic fragments thereof, are produced as described herein.
Animals, e.g., inbred strains of mice or rabbits, can be
immunized with an mTERT, such as the polypeptide of SEQ ID NO:2,
or with isoforms, homologues or immunogenic fragments thereof,
alone or using a standard adjuvant, such as Freund's adjuvant,
and a standard immunization protocol. Alternatively, a synthetic
peptide derived from the sequences disclosed herein and
conjugated to a carrier protein can be used an immunogen.
Polyclonal sera are collected and titered against the telomerase
in an immunoassay, for example, a solid phase immunoassay with
the telomerase immobilized on a solid support. Polyclonal
antisera with a titer of, e.g., 10<4 > or greater are
selected and tested for their cross reactivity against
homologous proteins from other organisms and/or non-telomerase
protein, using, e.g., a competitive binding immunoassay.
Specific monoclonal and polyclonal antibodies and antisera will
usually bind with a KD of at least about 1 [mu]M, preferably at
least about 0.1 [mu]M or better, and most preferably, 0.01 [mu]M
or less. However, the antisera and monoclonal antibodies of the
invention are not limited to these binding affinities.
[0183] ii. Immunological
Binding Assays
[0184] Immunological binding assays (e.g. U.S. Pat. Nos.
4,366,241; 4,376,110; 4,517,288; and 4,837,168) are known in the
art. For a review, see also METHODS IN CELL BIOLOGY Vol. 37:
Antibodies in Cell Biology, Asai, ed. Academic Press, Inc. New
York (1993); and Stites, supra. Immunological binding assays (or
immunoassays) typically utilize a capture agent to bind
specifically to and often immobilize the analyte. The capture
agent is a moiety that specifically binds to the analyte. In one
embodiment of the present invention, the capture agent is an
antibody that specifically binds to telomerase enzyme or mTERT.
[0185] Immunoassays also often utilize a labeling agent to
specifically bind to and label the binding complex formed by the
capture agent and the analyte, as described above. The labeling
agent may itself be, for example, one of the moieties comprising
the antibody/analyte complex: the labeling agent can be a
labeled mTERT or a labeled anti-mTERT antibody. Alternatively,
the labeling agent may be a third moiety, such as another
antibody, that specifically binds to the antibody-mTERT complex.
The labeling agent can be, for example, a second anti-mTERT
antibody bearing a label. The second antibody may lack a label,
but it may, in turn, be bound by a labeled third antibody
specific to antibodies of the species from which the second
antibody is derived. The second can be modified with a
detectable moiety, such as biotin, to which a third labeled
molecule can specifically bind, such as enzyme-labeled
streptavidin. Other proteins capable of specifically binding
immunoglobulin constant regions, such as protein a or protein G
may also be used as the label agent. These proteins are normal
constituents of the cell walls of streptococcal bacteria and
exhibit a strong non-immunogenic reactivity with immunoglobulin
constant regions from a variety of species (see, generally
Akerstrom (1985) J. Immunol. 135:2589-2542; Chaubert (1997) Mod.
Pathol. 10:585-591).
[0186] Throughout the assays, incubation and/or washing steps
may be required after each combination of reagents. Incubation
steps can vary from about 5 seconds to several hours, preferably
from about 5 minutes to about 24 hours. However, the incubation
time will depend upon the assay format, analyte, volume of
solution, concentrations, and the like. Usually, the assays will
be carried out at ambient temperature, although they can be
conducted over a range of temperatures, such as 10[deg.] C. to
40[deg.] C.
[0187] (1) Non-competitive
Assay Formats
[0188] Immunoassays for detecting murine telomerase enzyme and
mTERT protein may be, for example, either competitive or
noncompetitive. Noncompetitive immunoassays are assays in which
the amount of captured analyte (as mTERT) is directly measured.
In one preferred "sandwich" assay, for example, the capture
agent (anti-mTERT antibodies) can be bound directly to a solid
substrate where they are immobilized. These immobilized
antibodies then capture protein present in the test sample. The
mTERT protein thus immobilized is then bound by a labeling
agent, such as a second anti-mTERT antibody bearing a label.
Alternatively, the second anti-mTERT antibody may lack a label,
but it may, in turn, be bound by a labeled third antibody
specific to antibodies of the species from which the second
antibody is derived. The second can be modified with a
detectable moiety, such as biotin, to which a third labeled
molecule can specifically bind, such as enzyme-labeled
streptavidin.
[0189] (2) Competitive Assay
Formats
[0190] In competitive assays, the amount of analyte (telomerase)
present in the sample is measured indirectly by measuring the
amount of an added (exogenous) analyte (mTERT) displaced (or
competed away) from a capture agent (anti-TERT antibody) by the
analyte present in the sample. In one competitive assay, a known
amount of, in this case mTERT, usually labeled, is added to the
sample, and the sample is then contacted with a capture agent,
in this case an antibody that specifically binds mTERT. The
amount of labeled mTERT bound to the antibody is inversely
proportional to the concentration of mTERT present in the
sample. In another embodiment, the antibody is immobilized on a
solid substrate. The amount of mTERT bound to the antibody may
be determined either by measuring the amount of mTERT present in
an mTERT/antibody complex, or alternatively by measuring the
amount of remaining uncomplexed mTERT. The amount of mTERT may
be detected by providing a labeled mTERT molecule.
[0191] A hapten inhibition assay is another competitive assay.
In this assay a known analyte, in this case mTERT, is
immobilized on a solid substrate, a known amount of anti-mTERT
antibody is added to the sample, and the sample is then
contacted with the immobilized mTERT. In this case, the amount
of anti-mTERT antibody bound to the immobilized mTERT is
inversely proportional to the amount of telomerase or mTERT
present in the sample. The amount of immobilized antibody is
determined by detecting either the immobilized fraction of
antibody or the fraction of the antibody that remains in
solution. Detection may be direct where the antibody is labeled
or indirect by the subsequent addition of a labeled moiety that
specifically binds to the antibody, as described above.
[0192] Immunoassays in the competitive binding format can be
used for crossreactivity determinations to permit one of skill
to determine if a protein or enzyme complex is an mTERT or
murine telomerase enzyme. For example, an mTERT of SEQ ID NO:2
can be immobilized to a solid support, a putative mTERT protein
is added to the assay to compete with the binding of the
anti-mTERT sera to an immobilized mTERT. The ability of the
protein to compete with the binding of the antisera to the
immobilized mTERT is compared to the ability of soluble mTERT
(same as on the solid support) to compete with the binding of
the antisera to the immobilized mTERT.
[0193] (3) Other Assay Formats
[0194] The present invention also provides methods for Western
blot (inmmunoblot) analysis to detect and/or quantify the
presence of mTERT or telomerase enzyme protein in a sample. The
technique generally comprises separating sample proteins by gel
electrophoresis on the basis of molecular weight, transferring
the separated proteins to a suitable solid support (such as a
nitrocellulose filter, a nylon filter, or derivatized nylon
filter) and incubating the sample with antibodies that
specifically bind mTERT. The anti-mTERT antibodies specifically
bind to mTERT on the solid support. These antibodies may be
directly labeled or alternatively may be subsequently detected
using a second labeled antibody that specifically binds to the
anti-mTERT antibody.
[0195] Antibodies can also be used to probe expression
libraries, see Young (1982) Proc. Natl. Acad Sci. USA 80:1194.
In general, a cDNA expression library may be prepared from
commercially available kits or using readily available
components. Phage (Hurst (1997) Methods Mol Biol 69:155-159),
bacteria (Davis (1997) Proc. Natl. Acad. Sci. USA 94:2128-2132),
insect cells (Granziero (1997) J. Immunol. Methods 203:131-139),
yeast, and animal cells (Xenopus oocytes) can be used. One
selects mRNA from a source that is optionally enriched with the
target mRNA or in which the protein is abundant and creates cDNA
which is then ligated into a vector, and the vector is
transformed into the library host cells for immunoscreening.
Screening involves binding and identification of antibodies
bound to specific proteins on cells or immobilized on a solid
support such as nitrocellulose or nylon membranes. Positive
clones are selected for purification to homogeneity and the
isolated cDNA then prepared for expression in the desired host
cells. See also METHODS OF CELL BIOLOGY, VOL. 37, Antibodies in
Cell Biology, Assai (ed.) 1993.
[0196] The methods of the invention are also compatible with
other assay formats, including liposome immunoassays (LIA)
(Rongen (1997) J. Immunol. Methods 204:105-133), in which
liposomes designed to bind specific molecules (e.g., antibodies)
and release encapsulated reagents or markers are employed. The
released chemicals can be detected using standard techniques
(see, e.g. Monroe (1986) Amer. Clin. Prod. Rev. 5:34).
[0197] b. Purification and
Isolation of mTERT and Telomerase Enzyme
[0198] The methods and reagents of the invention enable one to
isolate and purify the naturally occurring and recombinantly
expressed murine telomerase enzyme and mTERT protein of the
invention from a variety of sources, such as larval homogenates,
bacterial cells, yeast, mammalian cells, human cells, tissue
culture media, transgenic plants and animals, to substantial
purity. For general information relating to standard
purification procedures, including selective precipitation with
such substances as ammonium sulfate; column chromatography,
immunopurification methods, and others see, for instance,
Scopes, R. K., Protein Purification: Principles and Practice,
2nd ed., Springer Verlag, (1987), U.S. Pat. No. 4,673,641,
Ausubel, and Sambrook. The purification of TERT polypeptides is
described herein and in related applications. The purification
of telomerase enzyme from a natural source is also described in
co-pending U.S. Ser. No. 08/833,377, filed Apr. 4, 1997. The
present invention also provides improvements to such methods
relating to antibodies against mTERT for purification, as well
as fusion proteins comprising a mTERT protein and a label that
aids purification.
[0199] i. Isolation of mTERT
from Bacterial Cultures
[0200] The present invention provides secreted recombinant mTERT
proteins which can isolated from the broth in which bacterial or
eukaryote cells have been cultured. In one embodiment, the
mTERT-encoding nucleic acids of the invention can be expressed
as a fusion protein with maltose-binding protein (MBP) or other
proteins or peptides fused thereto to increase the amount of
secreted and soluble product (see Chames (1997) FEBS Lett.
405:224-228); Sagiya (1994) Appl. Microbio.l Biotechnol.
42:358-363).
[0201] ii. Purification of
mTERT from Bacterial Cells
[0202] When recombinant mTERT protein is expressed in bacteria,
such as E. coli, the protein may be exported into the periplasm
of the bacteria. The periplasmic fraction of the bacteria can be
isolated by cold osmotic shock or by other methods known to
skill in the art; see Ausubel (1970) J. Biol. Chem. 245:4842;
Blight (1994) Curr. Opin. Biotechnol. 5:468-474. For example, to
isolate proteins from the periplasm, the cells are centrifuged
to form a pellet. The pellet can be resuspended in a buffer
containing, for example, 20% sucrose. To lyse the cells, cells
can be treated as described below. The suspension can be
centrifuged and the supernatant decanted and saved. The proteins
present in the supernatant can be separated and purified as
described herein.
[0203] iii. Purification of
mTERT from Inclusion Bodies
[0204] When recombinant mTERT and other telomerase enzyme
proteins are expressed by transformed bacteria or other cells in
large amounts, the proteins can form insoluble aggregates.
Purification of aggregate proteins, i.e., inclusion bodies,
typically involves extraction, separation and purification by
disruption of the cells, typically but not limited by,
incubation in a buffer of about 100-150 [mu]g/mL lysozyme and
0.1% NONIDET P40 a non-ionic detergent. The cell suspension can
be ground using a Polytron grinder (Brinkman Instruments,
Westbury, N.Y.). Alternatively, the cells can be sonicated on
ice. Alternate methods of lysing bacteria are described in
Ausubel and Sambrook and will be apparent to those of skill in
the art.
[0205] The cell suspension is centrifuged and the pellet
containing the inclusion bodies resuspended in buffer, e.g., 20
mM Tris-HCl (pH 7.2), 1 mM EDTA, 150 mM NaCl and 2% TRITON-X
100, a non-ionic detergent. The wash step may be repeated to
remove more cellular debris. The remaining pellet of inclusion
bodies may be resuspended in an appropriate buffer (e.g., 20 mM
sodium phosphate, pH 6.8, 150 mM NaCl). Other appropriate
buffers will be apparent to those of skill in the art. Following
the washing step, the inclusion bodies can be solubilized by the
addition of a solvent that is both a strong hydrogen acceptor
and a strong hydrogen donor (or a combination of solvents each
having one of these properties) together with a reducing agent
such as DTT. The proteins that formed the inclusion bodies can
then be renatured by dilution or dialysis with a compatible
buffer. Suitable solvents include, but are not limited to, urea
(typically from about 4 M to about 8 M), formamide (typically at
least about 80%, volume/volume basis), and guanidine
hydrochloride (typically from about 4 M to about 8 M). Some
solvents capable of solubilizing aggregate-forming proteins
include, e.g., SDS (sodium dodecyl sulfate), 70% formic acid,
but may be inappropriate if irreversible denaturation of the
proteins occurs, which is typically accompanied by a lack of
immunogenicity and/or activity. Although guanidine hydrochloride
and similar agents are denaturants, this denaturation is not
irreversible and renaturation may occur upon removal (by
dialysis, for example) or dilution of the denaturant, allowing
re-formation of immunologically and/or biologically active
protein. The protein can be separated during or after
solubilization from other bacterial or other contaminating host
proteins by standard separation techniques using the reagents of
the invention in accordance with the methods of the invention.
[0206] iv. Standard Protein
Separation Techniques
[0207] The present invention can provides methods for purifying
telomerase enzyme and mTERT from a natural source or as a
recombinant protein from transformed cells or transgenic
animals. The novel reagents of the invention, such as the
anti-mTERT antibodies, can be used to improve purification
procedures, such as those described in co-pending U.S. Ser. No.
08/833,377, filed Apr. 4, 1997. Some illustrative examples of
methods for purifying murine telomerase enzyme, mTERT, and other
compositions used in the methods of the invention are described
below.
[0208] (1) Solubility
Fractionation
[0209] If the protein mixture is complex, an initial salt
fractionation can separate many of the unwanted host cell
proteins (or proteins derived from the cell culture media) from
the protein of interest. The preferred salt is ammonium sulfate.
Ammonium sulfate precipitates proteins by effectively reducing
the amount of water in the protein mixture. Proteins then
precipitate on the basis of their solubility. The more
hydrophobic a protein is, the more likely it is to precipitate
at lower ammonium sulfate concentrations, a typical protocol is
to add saturated ammonium sulfate to a protein solution so that
the resultant ammonium sulfate concentration is between 20-30%.
This will precipitate the most hydrophobic of proteins. The
precipitate is discarded (unless the protein of interest is
hydrophobic), and ammonium sulfate is added to the supernatant
to a concentration known to precipitate the protein of interest.
The precipitate is then solubilized in buffer and the excess
salt removed if necessary, either through dialysis or
diafiltration. Other methods that rely on solubility of
proteins, such as cold ethanol precipitation, are well known to
those of skill in the art and can be used to fractionate complex
protein mixtures.
[0210] (2) Size Differential
Filtration
[0211] If the size of the protein of interest is known or can be
estimated from the cDNA sequence, proteins of greater and lesser
size can be removed by ultrafiltration through membranes of
different pore size (e.g., Amicon or Millipore membranes). As a
first step, the protein mixture is ultrafiltered through a
membrane with a pore size that has a lower molecular weight
cut-off than the molecular weight of the protein of interest.
The retentate of the ultrafiltration is then ultrafiltered
against a membrane with a molecular cut off greater than the
molecular weight of the protein of interest. The protein will
pass through the membrane into the filtrate. The filtrate can
then be chromatographed.
[0212] (3) Column
Chromatography
[0213] Proteins can be separated on the basis of their size, net
surface charge, hydrophobicity and affinity for ligands. In
addition, antibodies raised against proteins can be conjugated
to column matrices and the proteins immunopurified. All of these
general methods are well known in the art. See Scopes (1987)
supra. Chromatographic techniques can be performed at any scale
and using equipment from many different manufacturers (e.g.,
Pharmacia Biotech). Protein concentrations can be determined
using any technique, e.g., as in Bradford (1976) Anal. Biochem.
72:248-257.
[0214] v. Isolation of mTERT
and Murine Telomerase Enzyme
[0215] Telomerase can be isolated and purified by any of a
variety of means provided by the invention, as described above.
In one embodiment of the invention, telomerase enzyme can be
purified to over 60,000-fold purity over cytoplasmic crude cell
preparations. The steps to be included in a purification method
depend on the level of purification one desires. An illustrative
method to purify telomerase enzyme or mTERT protein from an
impure composition containing organic biomolecules to at least
60,000-fold compared to crude extract (about 4% relative purity)
can involve, e.g., (1) contacting the mTERT with a first matrix
that binds molecules bearing a negative charge, for example,
POROS 50 HQ, separating mTERT from other organic biomolecules
that do not bind to the matrix and collecting the mTERT; (2)
contacting the mTERT with a matrix that binds molecules bearing
a positive charge, for example POROS Heparin 20 HE-1, and
separating mTERT from other organic biomolecules that do not
bind to the matrix and collecting the mTERT; (3) contacting the
mTERT with a second matrix that binds molecules bearing a
negative charge, e.g., SOURCE 15Q, separating mTERT from other
organic biomolecules that do not bind to the matrix and
collecting the mTERT; (4) contacting the mTERT with an affinity
agent having specific affinity for mTERT, e.g., an
oligonucleotide complementary to the telomerase enzyme's RNA
moiety or an anti-mTERT antibody, separating mTERT from other
organic biomolecules that do not bind to the affinity agent and
collecting the mTERT; and/or (5) separating the mTERT from other
organic biomolecules according to molecular size, shape, or
buoyant density, e.g., separating molecules according to size on
a TosoHaas TSK-gel*G5000PWXL sizing column and collecting the
mTERT. The isolation and purification protocol also can include
the step of contacting the mTERT with an
intermediate-selectivity matrix, separating mTERT from other
organic biomolecules that do not bind to the
intermediate-selectivity matrix and collecting the mTERT,
preferably before the affinity step. mTERT can be isolated to
different levels of purity by altering, changing the sequence
of, or eliminating any of the steps in the purification
protocol. However, any preferred protocol will typically include
contacting the mTERT with an affinity agent, such as the
antibodies of the invention. Contacting the mTERT with at least
one matrix that binds molecules bearing a negative charge or a
positive charge is the next preferred step or steps to include
in the protocol.
[0216] c. Amino Acid Sequence
Determination
[0217] Illustrative amino acid sequences of mTERT of this
invention can be determined by, for example, Edman degradation,
a technique which is well known in the art. In addition to the
internal sequencing (see also Hwang (1996) J. Chromatogr. B.
Biomed. Appl. 686:165-175), N-terminal sequencing can be
performed by techniques known in the art. For C-terminal
sequence determination, a chemical procedure for the degradation
of peptides and analysis by matrix-assisted-laser-desorption
ionization mass spectrometry (MALDI-MS) can be used, see, e.g.,
Thiede (1997) Eur. J. Biochem. 244:750-754.
[0218] d. Molecular
Weight/Isoelectric Point Determination
[0219] The molecular weight of a protein can be determined by
many different methods, all known to one of skill in the art.
Some methods of determination include: SDS gel electrophoresis,
native gel electrophoresis, molecular exclusion chromatography,
zonal centrifugation, mass spectroscopy, and calculation from
sequencing. Disparity between results of different techniques
can be due to factors inherent in the technique. For example,
native gel electrophoresis, molecular exclusion chromatography
and zonal centrifugation depend on the size of the protein. The
proteins that are cysteine rich can form many disulfide bonds,
both intra- and intermolecular. Mobility under SDS gel
electrophoresis conditions depends on the binding of SDS to
amino acids present in the protein. Some amino acids bind SDS
more tightly than others, therefore, proteins will migrate
differently depending on their amino acid composition. Mass
spectroscopy and calculated molecular weight from the sequence
in part depend upon the frequency that particular amino acids
are present in the protein and the molecular weight of the
particular amino acid. If a protein is glycosylated, mass
spectroscopy results will reflect the glycosylation but a
calculated molecular weight may not.
[0220] The calculated molecular weight of mTERT (SEQ ID NO:2),
with a calculated length of 1122amino acids, is estimated to be
about 127 kD (specifically, 127,979 kD); and its apparent
molecular weight by SDS gel electrophoresis is estimated to be
between about 115 kD to about 140 kD. However, additional mTERT
proteins, mTERT isoforms, alleles and homologues within the
scope of the invention are not limited to this molecular weight
range.
[0221] The isoelectric point of a protein can be determined by
native gel (or disc) electrophoresis, isoelectric focussing or,
in a preferred method, by calculation given the amino acid
content of the protein (see, e.g., Wehr (1996) Methods Enzymol.
270:358-374; Moorhouse (1995) J. Chromatogr. a. 717:61-69,
describing capillary isoelectric focusing). The isoelectric
point (pI) of mTERT (SEQ ID NO:2) has been calculated to be
about 10.4. However, mTERT alleles, isoforms and homologues,
within the scope of the invention are not limited to this range
of isoelectric points.
[0222] e. mTERT Fusion Proteins
[0223] The mTERT of the invention can also be expressed as a
recombinant protein with one or more additional polypeptide
domains linked thereto to facilitate protein detection,
purification, or other applications. Such detection- and
purification-facilitating domains include, but are not limited
to, metal chelating peptides such as polyhistidine tracts and
histidine-tryptophan modules that allow purification on
immobilized metals, protein a domains that allow purification on
immobilized immunoglobulin, and the domain utilized in the FLAGS
extension/affinity purification system (Immunex Corp, Seattle
Wash.). The inclusion of a cleavable linker sequences such as
Factor Xa or enterokinase (Invitrogen, San Diego Calif.) between
the purification domain and telomerase or telomerase-associated
protein(s) may be useful to facilitate purification. One such
expression vector provides for expression of a fusion protein
comprising the sequence encoding an mTERT of the invention and
nucleic acid sequence encoding six histidine residues followed
by thioredoxin and an enterokinase cleavage site (e.g., see
Williams (1995) Biochemistry 34:1787-1797). The histidine
residues facilitate detection and purification while the
enterokinase cleavage site provides a means for purifying the
desired protein(s) from the remainder of the fusion protein.
Technology pertaining to vectors encoding fusion proteins and
applications of fusion proteins are well described in the patent
and scientific literature, see e.g., Kroll (1993) DNA Cell.
Biol., 12:441-53.
3. Assaying for Telomerase
Activity
[0224] The assays described below can be used to detect, assess
the purity of and quantify isolated or recombinant mTERT
produced in bacteria, insect and yeast, tissue culture fluid and
plant and animal tissues, or other, including natural, sources.
The activity assays described below and provided by the present
invention can be used to identify compositions which modulate
mTERT, i.e., modify, activate or inhibit, the activity of
telomerase, ie., act as antagonists or agonists of
telomerase-mediated DNA replication.
[0225] a. Measuring an Increase
or Decrease in the Length of Telomeres
[0226] Because telomerase enzyme extends telomerase DNA, and
because telomeres shorten as cells divide in the absence of
telomerase, one can indirectly detect mTERT or telomerase enzyme
by measuring telomere length. Assays well known in the art that
can be used to determine the length of telomeres include
restriction endonuclease digestion and probing as well as a
modified Maxam-Gilbert reaction, see e.g., WO 93/23572; WO
95/13382; WO 96/41016; U.S. Pat. Nos. 5,645,986; 5,707,795; and
5,686,245.
[0227] Direct fluorescence in situ by fluorochrome-labeled
nucleic acid probes enables determination of the presence and
location of DNA sequences complementary to the labeled probe.
Without further amplification, this method can be limited to
detecting targets with middle to high copy numbers. However,
both signal and target amplification is possible, for example,
with labeled antibody (as a fluorochrome) specific for a label
which is covalently attached to the nucleic acid probe, as
discussed above; also, see Schwarzacher (1994) "Direct
fluorochrome-labeled DNA probes for direct fluorescent in situ
hybridization to chromosomes" Methods Mol. Biol. 28:167-176.
[0228] In one embodiment of the invention, telomerase
enzyme-generated products or telomeric structures are detected
using a variation of an antibody amplification technique, the
so-called catalyzed signal amplification (CSA) technique. This
immunohistochemical assay allows in situ visualization of the
telomere (or any composition) of interest. In one variation,
incubation with primary antibody is followed by secondary
antibody conjugated to biotin, followed by a
strepavidin-biotin-peroxidase complex, biotinyl-tyramide reagent
and 3,3'-diaminobenzidine tetrahydrochloride (see Sanno (1996)
Am. J. Clin. Pathol. 106:16-21; Sanno (1997) Neuroendocrinology
65:299-306).
[0229] b. In Vitro Telomerase
Activity Assays
[0230] In one embodiment, the mTERT protein of the invention is
used to reconstitute telomerase activity. Such reconstitution is
useful not only for detecting modulators of telomerase-mediated
DNA replication in in vitro activity assays, but also for
identifying mTERT polypeptides and telomerase enzymes, including
mTERT isoforms, alleles and homologues.
[0231] i. Detecting Telomerase
Activity Using Immobilized Enzyme
[0232] In one embodiment of the invention, telomerase activity
is monitored in a solid-phase system using the so-called
catalyzed reporter deposition (CARD) system. Telomerase enzyme
or mTERT is immobilized onto a solid phase using the antibodies
of the invention or chemical linkers, and the like. To assay
fill or a "partial" mTERT or telomerase enzyme activity, a
telomerase enzymatic reaction is carried out in a buffered
aqueous solution compatible with the assayed telomerase
activity. The appropriate reagents are added to detect the
activity, for example, to allow the telomerase to catalyze
multiple copies of detectable, reaction product. For general
information, see Bobrow (1992) "The use of catalyzed reporter
deposition as a means of signal amplification in a variety of
formats" J. Immunol. Methods 150:145-149; and Schmidt (1997)
"Signal amplification in the detection of single-copy DNA and
RNA by enzyme-catalyzed deposition (CARD) of the novel
fluorescent reporter substrate Cy3.29-tyramide" J. Histochem.
Cytochem 45:365-373.
[0233] c. Incorporation of
Labeled Nucleotides-Primer Extension
[0234] One method which assays for telomerase activity in cell
samples relies on the incorporation of radioactively or
otherwise labeled nucleotides into newly synthesized
polynucleotides by elongation of a telomerase substrate, i.e.,
the telomerase extension product. Briefly, this assay measures
the amount of nucleotides incorporated into polynucleotides
synthesized on a primer sequence. The amount incorporated is
typically measured as a function of the intensity of a band on a
phosphor screen, such as the PhosphorImager(R) or FluorImager(R)
(Molecular Dynamics, Sunnyvale, Calif.) exposed to a gel on
which the radioactive products are separated. See Morin (1989)
Cell 59:521-529.
[0235] Conventional "primer extension" assays use an
oligonucleotide substrate, a radioactive deoxyribonucleotide
triphosphate (dNTP) for labeling the extended substrate, and gel
electrophoresis for resolution and display of telomerase
extension products. Because telomerase stalls and can release
the DNA after adding the first G in the 5'-TTAGGG-3' (SEQ ID
NO:7) telomeric repeat, the characteristic pattern of products
detected on the gel is a six nucleotide ladder of extended
oligonucleotide substrates. The phase of the repeat depends on
the 3' end sequence of the substrate; telomerase recognizes
where the end is in the repeat and synthesizes accordingly to
yield contiguous, repetitive sequences. As noted above, the
nucleotides, substrate, and extended substrate can be
alternatively labeled with non-radioactive means such as
fluorescent, phosphorescent, or chemiluminescent labels. The
nucleotides or extended substrate can be "tagged," where the
"tag" can be identified by a second labeled molecule. For
example, the tag can be biotin. The resultant tagged nucleotide
can be recognized by using a labeled avidin, such as
avidinylated horseradish peroxidase, followed by a chromogenic
substrate, as, e.g., in Durrant (1996) Mol. Biotechnol. 6:65-67.
Many variations on these detection formats are well known in the
art.
[0236] i. Dot Blot Assay
[0237] Another assay for telomerase activity is the dot blot
assay. The dot blot assay is useful for routine screening
because it can be used in high throughput mode, and hundreds of
assays can be carried out in a single day with a good portion of
the labor performed automatically. The dot blot assay is most
effective for comparing activity of samples at roughly the same
level of purity and is less effective for a multiplicity of
samples at different stages of purity, and so may not be a
preferred assay for determining relative purity. See co-pending
U.S. Ser. No. 08/833,377, filed Apr. 4, 1997.
[0238] ii. Reverse
Transcription PCR/Quantitative PCR
[0239] The present invention provides polymerase chain reaction
(PCR) assays that can be used to detect and quantify levels of
telomerase enzyme-generated product. See also, U.S. Pat. No.
5,629,154. Other target amplification techniques can also be
employed in these methods, and one of skill in the art will
appreciate that, whatever amplification method is used, if a
quantitative result is desired, care must be taken to use a
method that maintains or controls for the relative amplification
of the various nucleic acids amplified. PCR is discussed in
general above, a comprehensive discussion on quantitative PCR
can be found in the scientific and patent literature, and is,
for example, outlined in Innis, supra; see also Okamoto (1997)
Biol. Pharm. Bull. 20:1013-1016.
[0240] iii. Telomeric Repeat
Amplification Protocol (TRAP Assay)
[0241] The invention also provides for novel embodiments of the
TRAP assay and variations of this well known telomerase activity
assay. The present invention provides reagents useful for the
TRAP assay as well as new amplification based telomerase
activity assays for a wide variety of applications.
[0242] One limitation of the primer extension assay, described
above, for assessing telomerase activity is weak signal
strength, often necessitating long (7 or more days)
autoradiographic exposure. Fortunately, the highly sensitive
PCR-based "TRAP" assay for measuring telomerase activity has
been developed. The TRAP assay is an amplification-based method
for detecting, determining, and measuring telomerase activity
and is described in PCT Publication Nos. WO 97/15687 and WO
95/13381 and U.S. Pat. No. 5,629,154; see also U.S. Ser. No.
08/632,662, and U.S. Ser. No. 08/631,554, filed 15 Apr. 1996 and
12 Apr. 1996, respectively. See also, Kim (1994) Science
266:2011; PCT/US96/09669; Piatyszek (1995) Methods in Cell
Science 17:1-15; Krupp (1997) Nuc. Acids Res. 25:919-921; Kim
(1994) Science 266:2011-2015; Wright (1995) Nucleic Acids Res.
23 :3794-3795; Tatematsu (1996) Oncogene 13:2265-2274; and Kim
(1997) Nuc. Acids Res. 25:2595-2597.
[0243] The TRAP assay allows one to measure the elongation of a
short oligonucleotide primer known to act as an efficient
substrate of telomerase enzyme. Telomerase is an RNA-dependent
DNA polymerase that normally synthesizes telomeric repeats at
the 3' end of the leading DNA strand. mTERC and hTERC can
function as templates for the extension of a chromosomal end.
hTERT synthesizes telomeric repeats (TTAGGG)n (SEQ ID NO:7) onto
the 3' end of a telomerase substrate oligonucleotide ("TS"),
5'-AATCCGTCGAGCAGAGTT-3' (SEQ ID NO:6). Although the TS sequence
lacks TTAGGG (SEQ ID NO:7) repeats, it is a good human
telomerase enzyme substrate (first described in Morin, (1991)
Nature 353:454-456). The TS substrate lacks TTAGGG repeats,
allowing for forward PCR amplification primers specific for
extended TS. The forward, or other primer of the primer pair
anneals only to the TTAGG (SEQ ID NO:7) repeats added by the
telomerase to TS, and that primer pair enables efficient
amplification of the extended TS. mTERT activity can be assayed
using this TRAP model, as demonstrated in the Example, below.
[0244] For use of internal controls in TRAP assays, see the
publications cited supra and, e.g., Yashima (1997) "Telomerase
activity and in situ telomerase RNA expression in malignant and
non-malignant lymph nodes" J. Clin Pathol 50:110-117.
[0245] iv. Reconstitution of
Activity In Vitro
[0246] In one embodiment of the invention, using mTERT encoding
nucleic acid, telomerase enzyme activity, full or "partial," is
reconstituted in vitro in an appropriate in vitro translation or
transcription/translation system, many of which are commercially
available, e.g., RiboMAX(TM) Large Scale RNA Production System,
Flexi Rabbit Reticulocyte Lysate System, Promega Corp., Madison,
Wis. In alternative embodiments, the RNA component of the
mTERT-containing telomerase enzyme complex can be mTERC or
hTERC: Other telomerase-associated proteins can also be
co-expressed in the system.
[0247] d. In Vivo/In Situ
Telomerase Activity Assays-Reconstitution of Activity
[0248] The present invention provides methods for identifying
modulators of mTERT-containing telomerase enzyme-mediated DNA
replication by in vitro, in vivo and in situ activity assays.
Methods for identifying modulators of telomerase activity have
been described. See, e.g., U.S. Pat. No. 5,645,986; and Ser. No.
08/288,501, filed Aug. 10, 1994. The present invention provides
improvements to these known methods by providing highly purified
murine telomerase enzyme, mTERT, as well as anti-mTERT
antibodies for use as controls or agents. The present invention
also provides activity assays that can identify modulators of
full or a partial activity of mTERT or telomerase enzyme.
[0249] In certain embodiments, assay formats are chosen that
detect the presence, absence or abundance of either a telomerase
enzyme or mTERT protein, a telomerase- or mTERT-generated
product, an mTERT isoform, allele, or homologue, in each cell in
a sample or in a representative sampling. Examples of such
formats include those that detect a signal by histology, e.g.,
immunohistochemistry, and with nucleic acids, either including
signal-enhancing steps, such as in situ nucleic acid
amplification followed by fluorescence-activated cell sorting
(FACS-PCR). These formats are particularly advantageous when
dealing with a highly heterogeneous cell population, e.g.,
containing multiple cell types from among which only one or a
few types have elevated mTERT levels.
[0250] In vivo assays include non-human cell systems into which
recombinant mTERT is expressed. The RNA moieties mTERC or hTERC
can either be simultaneously co-expressed with mTERT or hTERT to
generate telomerase enzyme activity. Other murine
telomerase-associated proteins can also be co-expressed in this
in vivo assay system. This reconstitution of full or "partial"
telomerase activity using mTERT in vivo provides for a method of
screening for telomerase modulators in cells or animals from any
origin. Telomere length can also be measured, as described
above.
[0251] Telomerase enzyme antagonists that can cause or
accelerate loss of telomeric structure can be identified by
monitoring and measuring their effect on mTERT or telomerase
enzyme activity in vivo, ex vivo, or in vitro, or by their
effects on telomeric length (as through staining or use of
tagged hybridization probes) or, simply, through cell death of
telomerase positive cancer cells (critical shortening of
telomeres leads to a phenomenon termed "crisis" or M2 senescence
(Shay (1991) Biochem. Biophys. Acta 1072:1-7), which cancer
cells can bypass by activating telomerase or another telomere
length maintenance pathway but which otherwise will lead to
their death through chromosomal deletion and rearrangement).
[0252] The present invention also provides assays that can also
be used to screen for agents that increase the full or a
"partial" activity of telomerase, either by causing TERT protein
or telomerase to be expressed in a cell in which it normally is
not expressed or by increasing telomerase activity levels in
telomerase positive cells. Such agonists can be identified in an
activity assay of the invention or by their effect on telomere
length or both.
[0253] i. Administering
Telomerase-activity-modulators to Mortal Cells
[0254] In one embodiment, the invention provides recombinant
mTERT and mTERT-containing telomerase enzyme and necessary
telomerase enzyme complex components for expression in normal,
diploid mortal cells to create indefinitely proliferating cells,
to immortalize those cells, or to increase their proliferative
capacity. For example, expression of mTERT of the invention can
be used to create immortal or indefinitely proliferating B
lymphocytes. In another embodiment, mortal cells that produce a
commercially desirable protein, such as pituitary cells, are
immortalized or made indefinitely proliferating by expression of
an mTERT, e.g., as that of SEQ ID NO:2.
[0255] In another embodiment, the invention provides means to
inhibit the expression or activity of telomerase enzyme in a
cell to be used for transplantation into a host so that the
transplanted cell cannot become immortalized or indefinitely
proliferating. This method is ideal for cells that have been
modified to delete histocompatibility antigens or modified in
some way to prevent or decrease the possibility of immune
rejection, because such cells are preferred for transplantation.
Reintroduction of normal cells into an individual presents a
risk that the cells may change to a state of uncontrolled cell
growth, becoming a malignancy. The present invention prevents
this complication by "knocking out" or inhibiting (antagonizing)
telomerase activity (or a telomerase enzyme complex component
necessary for activity). Without an active telomerase, the cells
are "irreversibly mortal," decreasing the probability of
malignant transformation after reintroduction.
[0256] When reconstituting telomerase activity in mortal cells,
in which telomerase activity normally cannot be detected,
generation of a maximum level of telomerase activity may
necessitate co-expression of mTERT with other components,
especially such as mTERC, and in some cases, other
telomerase-associated proteins.
[0257] ii. Administering
Telomerase-activity-modulators to Immortal Cells
[0258] Antagonists of telomerase-mediated DNA replication can be
identified by administering the putative inhibitory composition
to a cell that is known to exhibit significant amounts of
telomerase activity, such as cancer cells or indefinitely
proliferating cells. Such compositions so identified can then be
used to treat diseases, such as cancer, that are exacerbated by
or caused by or depend on a minimum level of telomerase
expression or activity. Telomerase enzyme-positive cells can be
tumor cell lines, isolated from in vivo sources, or present in
an intact animal, as for example, in a solid tumor.
Reconstitution of activity by the methods and with the reagents
of the invention in an in vitro system, cell or animal using
mTERT, mTERC, and/or other telomerase-associated components,
allows one to screen for antagonists by assaying or monitoring
the expected decrease in telomerase activity, or accelerated
loss of telomeric length, or senescence (cancer cells that
continue to divide despite critical telomere shortening die in
the absence of telomerase activity).
[0259] iii. Transgenic Animals
Incorporating mTERT Genes
[0260] The introduction of mTERT or other TERT genes into mice
to create transgenic mice can be used to assess the consequences
of mutations or deletions to the coding or transcriptional
regulatory (e.g., promoter) regions. In one embodiment, the
endogenous mTERT gene in these mice is still functional and
wild-type (native) telomerase activity can still exist. With the
use of a promoter that drives high level expression of the
exogenous TERT construct, the endogenously produced mTERT
protein can be competitively replaced with the introduced,
exogenous TERT protein. This transgenic animal (retaining a
functional endogenous telomerase activity) is preferred in
situations where it is desirable to retain "normal," endogenous
telomerase function and telomere structure.
[0261] In other situations, where it is desirable that all
telomerase activity is by the introduced exogenous TERT protein,
use of an mTERT knockout line (described below) is preferred.
[0262] Promoter function, and in a preferred embodiment, mTERT
promoter function, can be assessed with mTERT transgenic
animals. Alterations of mTERT promoters can be constructed that
drive mTERT or a reporter gene to assess their function and
expression pattern and characteristics (the invention also
provides constructs and methods for gene expression driven by an
mTERT promoter by transient transfection). In one embodiment,
the ability of an mTERT promoter to limit the expression of a
cell killing gene (e.g., thymidine kinase or ricin) to cancer
cells can be assessed. The genomic regions that confer
developmental and tissue specific expression can be identified.
This could lead to the identification of proteins or other
transcriptional trans-activators that modulate gene, e.g.,
mTERT, expression. Proteins that modulate mTERT expression are
attractive targets for therapeutic intervention either for
inhibition of telomerase activity in cancer cells or for the
extension of replicative lifespan in normal cells and other uses
as described herein.
[0263] Transgenic animal or cells expressing mTERT proteins in
an inappropriate manner can also be constructed. Promoters can
be used that give constitutive expression in all tissues or
developmental stages or limit expression to specific cell types
or tissues. In this manner the biological consequences of an
mTERT native or altered protein can be assessed in vivo or ex
vivo.
[0264] Transgenic animals or cells expressing mutant (i.e.,
non-native) mTERT proteins can also be constructed. This will
provide an in vivo or ex vivo model system to assess the
structure and function of mTERT amino acid sequences on
telomerase or telomere function.
[0265] iii. Telomerase Knockout
Cells and Animal Models
[0266] The invention also includes "knockout" cells and animals,
in which one or several units of the endogenous telomerase
enzyme complex have been deleted, altered, or inhibited. These
"knockout" cells and animals can serve as a model useful in drug
discovery and development, and include modified cells or animals
with increased amounts of endogenous, modified endogenous or
exogenous telomerase enzyme activity. Reconstitution of
telomerase activity can save the cell or animal from the
inevitable cell death caused by inability to maintain telomeres.
[0267] Methods of altering the expression of endogenous genes
are well known to those of skill in the art. Typically, such
methods involve altering or replacing all or a portion of the
regulatory sequences controlling expression of the particular
gene to be regulated The regulatory sequences, e.g., the native
promoter can be altered. One technique for targeted mutation of
genes involves placing a genomic DNA fragment containing the
gene of interest into a construct, i.e., a vector. An example of
such a vector includes the cloning of two genomic regions
flanking the gene of interest around a selectable
neomycin-resistance cassette in a vector containing a thymidine
kinase gene. See also Westphal (1997) Curr. Biol. 7:530-533.
This "knock-out" construct is then transfected into the
appropriate host cell, ie., a mouse embryonic stem (ES) cell, as
discussed in detail above.
[0268] e. Quantitation of
Telomerase Activity
[0269] Telomerase enzyme activity can be quantified in a variety
of ways, depending on the method of measurement and convenience.
Telomerase activity can be expressed in terms of the amount of
mTERT, telomerase enzyme or telomerase-generated product in a
sample, which can be expressed as standard units of weight per
quantity of biological sample (e.g., picograms per gram tissue,
picograms per number of cells, etc.), as a number of molecules
per quantity of biological sample (e.g., molecules/cell,
moles/cell, etc.) or some similar method, or may be expressed
using arbitrary units (e.g., comparing a normal cells from an
individual to indefinitely proliferating or immortal, cancer
cells). The quantity of mTERT, telomerase enzyme or
telomerase-generated product can also be expressed in relation
to the quantity of another molecule, ie., the number of mTERT
molecules (of gene, protein or mRNA transcript) per sample per
number of 28S rRNA transcripts in sample; nanograms of mTERT
protein per nanograms of actin, and the like.
[0270] When measuring mTERT, telomerase or telomerase-generated
product in two (or more) different samples, it will sometimes be
useful to have a common basis of comparison of the two samples.
When comparing a sample of normal tissue and a sample of
cancerous tissue, equal amounts of tissue (by weight, volume,
number of cells, etc.) can be compared. Alternatively,
equivalents of a marker molecule (e.g., 28S rRNA, mTERC, actin)
may be used. For example, the amount of telomerase or
telomerase-generated product in a healthy tissue sample
containing 10 picograms of 28S rRNA can be compared to a sample
of tissue containing the same amount of 28S rRNA.
[0271] In certain embodiments, assay formats are chosen that
detect the abundance of an mTERT isoform, allele or homologue in
each cell in a sample in situ. Examples of such formats include
those that detect the intensity of a signal by
immuno-histochemistry with nucleic acid signal-enhancing steps,
such as in situ nucleic acid amplification followed by
fluorescence-activated cell sorting (FACS-PCR). These formats
are particularly advantageous when dealing with a highly
heterogeneous cell population, e.g., containing multiple cells
types or which only one or a few types have elevated mTERT
levels. General methodology related to this technique is
described in Cao (1995) "Identification of malignant cells in
multiple myeloma bone marrow with immunoglobulin VH gene probes
by fluorescent in situ hybridization and flow cytometry" J.
Clin. Invest. 95:964-972.
[0272] It is not always necessary to quantify mTERT mRNA or
protein or to detect a full or partial telomerase enzyme
activity. Often the detection of an mTERT gene product will be
sufficient for a diagnosis, as under assay conditions in which
the telomerase activity or telomerase-generated product is not
detectable in control, e.g., nonmalignant, normal cells. As
another example, when the levels of product found in a test
(e.g., tumor) and control (e.g., mortal cell) samples are
directly compared, quantitation of mTERT is not necessary to
make an accurate determination.
[0273] i. Quantitating Amounts
of Nucleic Acid in a Sample to Determine Telomerase Activity:
Methodologies
[0274] Telomerase enzyme activity can be expressed in terms of
the amount of telomerase-generated product in a sample, i.e.,
the amount of telomere DNA synthesized by the enzyme complex.
Quantitation of RNA is also useful for determining the
transcriptional efficiency of recombinant DNA in expression
systems, such as with in vitro transcription, antisense RNA
expression, transfection of mortal, indefinitely proliferating
or immortal cells and transgenic animals.* Evaluating levels of
RNA is also useful in evaluating cis- or trans-transcriptional
regulators.
[0275] General techniques for quantitating amount of nucleic
acids in samples are well known in the art, as are described,
e.g., see Diaco in Innis (1995) PCR Strategies, supra,
"Practical Considerations for the design of quantitative PCR
assays", pg. 84-108. Branched DNA signal amplification is
described in Urdea (1994) Bio/Tech. 12:926, and U.S. Pat. No.
5,124,246.
[0276] f. Partial Activity
Telomerase Assays
[0277] In one embodiment of the invention, a variety of partial
activity telomerase assays are provided to identify a variety of
different classes of modulators of telomerase activity. The
"partial activity" assays of the invention allow identification
of classes of telomerase activity modulators that might
otherwise not be detected in a "full activity" telomerase assay.
One partial activity assay involves the non-processive activity
of mTERT and telomerase enzyme. The processive nature of
telomerase activity is described by Morin (1989) supra; see also
Prowse (1993) "Identification of a nonprocessive telomerase
activity from mouse cells" Proc. Natl. Acad. Sci. USA
90:1493-1497. Another partial activity assay of the invention
exploits the "reverse-transcriptase-like" activity of
telomerase. In these assays, one assays the reverse
transcriptase activity of the mTERT protein or telomerase
enzyme. See Lingner (1997) "Reverse transcriptase motifs in the
catalytic subunit of telomerase" Science 276:561-567. Another
partial activity assay of the invention exploits the
"nucleolytic activity" of mTERT and telomerase enzyme, involving
the enzyme's removing of at least one guanine "G" residue from
the 3' strand. This nucleolytic activity has been observed in
the Tetrahymena telomerase by Collins (1993) "Tetrahymena
telomerase catalyzes nucleolytic cleavage and nonprocessive
elongation" Genes Dev 7:1364-1376. Another partial activity
assay of the invention involves analyzing mTERT's and telomerase
enzyme's ability to bind nucleotides as part of its
enzymatically processive DNA polymerization activity. Another
partial activity assay of the invention involves analyzing
mTERT's or telomerase enzyme's ability to bind its RNA moiety,
ie., mTERC, used as a template for telomere synthesis.
[0278] Additional partial activity assays of the invention
involve analyzing mTERT's and telomerase enzymes's ability to
bind chromosomes in vivo, or to bind oligonucleotide primers in
vitro or in reconstituted systems, or to bind proteins
associated with chromosomal structure (see, for an example of
such a protein, Harrington (1995) J Biol Chem 270: 8893-8901).
Chromosomal structures which bind mTERT include, for example,
telomeric repeat DNA, histones, nuclear matrix protein, cell
division/cell cycle control proteins and the like. One of skill
in the art can use the methods of the invention to identify
which portions (e.g., domains) of these telomerase-associating
proteins contact telomerase. In one embodiment of the invention,
these TERT-binding and telomerase-associating proteins or
fragments thereof are used as modulators of telomerase activity.
4. Modulators of Telomerase
Activity
[0279] The invention provides methods and reagents for screening
for compositions or compounds capable of modifying the ability
of mTERT and mTERT-containing telomerase enzyme to synthesize
telomere DNA ("full activity"). The invention also screens for
modulators of any or all of mTERT's "partial activities," some
of which are described above. In various embodiments, the
invention includes, but is not limited to, screening for
antagonists that: bind to mTERT's active site; inhibit the
association of its RNA moiety, telomerase-associated proteins,
nucleotides, or telomeric DNA to the telomerase enzyme or mTERT
protein; promote the disassociation of the enzyme complex; or
inhibit any of the "partial activities" described above.
[0280] Screening for antagonist activity provides for
compositions that decrease telomerase enzyme activity, thereby
preventing unlimited cell division of cells exhibiting
unregulated cell growth, such as cancer cells. Telomerase enzyme
activity has been identified as an important cancer marker, one
whose levels can diagnose, prognose, and predict the outcome or
seriousness of disease, as described in U.S. Pat. Nos.
5,489,508; 5,648,125; and 5,639,613. The present invention
provides mTERT antagonists which can also inhibit the activity
of hTERT, or can serve as a structural basis for developing
hTERT antagonists, thus providing useful reagents for treating
cancer by modulating telomerase activity.
[0281] Screening for agonist activity provides for compositions
that increase telomerase's activity in a cell. Such agonist
compositions provide for methods of creating a state of
continuous proliferation or immortalizing otherwise normal,
untransformed cells, including cells which can express useful
proteins, as discussed above. Such agonists also provide for
methods of controlling or delaying cellular senescence. The
present invention provides mTERT agonists which can also
increase the activity of hTERT, or can serve as a structural
basis for developing hTERT agonists.
[0282] The methods of the invention are amenable to adaptations
from protocols described in the scientific and patent literature
and known in the art. For example, when a telomerase enzyme or
mTERT protein of this invention is used to identify compositions
which act as modulators of telomerase enzyme activities, large
numbers of potentially useful molecules can be screened in a
single test. The modulators can have an inhibitory (antagonist)
or potentiating (agonist) effect on telomerase activity. For
example, if a panel of 1,000 inhibitors is to be screened, all
1,000 inhibitors can potentially be placed into one microtiter
well and tested simultaneously. If such an inhibitor is
discovered, then the pool of 1,000 can be subdivided into 10
pools of 100 and the process repeated until an individual
inhibitor is identified.
[0283] a. Synthetic Small
Molecule Modulators
[0284] Potential modifiers of telomerase activity, i.e., test
compounds, preferably of molecular weight under about 10,000
daltons; more preferably, under about 5,000 daltons; and most
preferably, under about 500 daltons, include synthetic
molecules, which can be designed and produced for testing by any
technique, many of which are described in the patent and
scientific literature, and a few illustrative examples are
described below.
[0285] i. Combinatorial
Chemistry Methodology
[0286] The creation and simultaneous screening of large
libraries of synthetic molecules can be carried out using
well-known techniques in combinatorial chemistry, e.g., see van
Breemen (1997) Anal. Chem. 69:2159-2164; Lam (1997) Anticancer
Drug Des. 12:145-167 (1997); Shipps (1997) Proc. Natl. Acad.
Sci. USA 94:11833-11838; Kaur (1997) J. Protein Chem.
16:505-511; Zhao (1997) J. Med. Chem. 40:4006-4012, for
screening solution-phase combinatorial libraries using pulsed
ultrafiltration/electrospray mass spectrometry.
[0287] ii. Rational Drug Design
[0288] Rational drug design involves an integrated set of
methodologies that include structural analysis of target
molecules, synthetic chemistries, and advanced computational
tools. When used to design modulators, such as
antagonists/inhibitors of protein targets, such as mTERT protein
and mTERT-containing telomerase enzyme, the objective of
rational drug design is to understand a molecule's
three-dimensional shape and chemistry. Rational drug design is
aided by X-ray crystallographic data or NMR data, which can now
be determined for the mTERT protein and telomerase enzyme in
accordance with the methods and using the reagents provided by
the invention. Calculations on electrostatics, hydrophobicities
and solvent accessibility are also helpful. See, e.g., Coldren
(1997) Proc. Natl. Acad. Sci. USA 94:6635-6640.
[0289] b. Inhibitory
(Antagonist) and Activator (Agonist) Peptide Modulators
[0290] Potential modulators of mTERT and telomerase enzyme
activity also include peptides. For example, oligopeptides with
randomly generated sequences can be screened to discover peptide
modulators (agonists or inhibitors) of mTERT and/or telomerase
activity. Such peptides can be used directly as drugs or to find
the orientation or position of a functional group that can
inhibit telomerase activity that, in turn, leads to design and
testing of a small molecule inhibitor. Peptides can be
structural mimetics, and one can use molecular modeling programs
to design mimetics based on the characteristic secondary
structure and/or tertiary structure of telomerase enzyme and
mTERT protein. Such structural mimetics can also be used
therapeutically, in vivo, as modulators of telomerase activity
(agonists and antagonists). Structural mimetics can also be used
as immunogens to elicit anti-mTERT protein antibodies.
[0291] c. Inhibitory Natural
Compounds as Modulators of Telomerase Activity
[0292] In addition, a large number of potentially useful
activity-modifying compounds can be screened in extracts from
natural products as a source material. Sources of such extracts
can be from a large number of species of fungi, actinomyces,
algae, insects, protozoa, plants, and bacteria. Those extracts
showing inhibitory activity can then be analyzed to isolate the
active molecule. See, e.g., Nisbet (1997) Curr. Opin.
Biotechnol. 8:708-712; Turner (1996) J. Ethnopharmacol. 51:3943;
Borris (1996) J. Ethnopharmacol. 51:29-38; Suh (1995) Anticancer
Res. 15:233-239.
[0293] d. Inhibitory
Oligonucleotides
[0294] One particularly useful set of inhibitors provided by the
present invention includes oligonucleotides that are able to
either bind mRNA encoding mTERT protein or to the mTERT gene, in
either case preventing or inhibiting the production of
functional mTERT protein. Other oligonucleotides of the
invention interact with mTERT's RNA moiety, or are able to
prevent binding of telomerase enzyme or mTERT to its
DNA/telomere target, or one telomerase component to another, or
to a substrate. Such oligonucleotides can also bind the
telomerase enzyme or mTERT protein and inhibit a partial
activity, as described above (such as its processive activity,
its reverse transcriptase activity, its nucleolytic activity,
and the like). The association can be though sequence specific
hybridization to another nucleic acid or by general binding, as
in an aptamer.
[0295] Another useful class of inhibitors includes
oligonucleotides which cause inactivation or cleavage of mTERT
mRNA or mTERC. That is, the oligonucleotide is chemically
modified or has enzyme activity which causes such cleavage, such
as is the case with ribozymes. As noted above, one may screen a
pool of many different such oligonucleotides for those with the
desired activity.
[0296] Another useful class of inhibitors includes
oligonucleotides which bind polypeptides. Double- or
single-stranded DNA or single-stranded RNA molecules that bind
to specific polypeptide targets are called "aptamers." The
specific oligonucleotide-polypeptide association may be mediated
by electrostatic interactions. For example, aptamers
specifically bind to anion-binding exosites on thrombin, which
physiologically binds to the polyanionic heparin (Bock (1992)
Nature 355:564-566). Because mTERT protein binds both mTERC (or
hTERC) and its DNA substrate, and because the present invention
provides mTERT and other mTERT-associated proteins in isolated
and purified forms in large quantities, those of skill in the
art can readily screen for mTERT-binding aptamers using the
methods of the invention.
[0297] Antagonists of telomerase-mediated DNA replication can
also be based on inhibition of mTERC (Norton (1996) Nature
Biotechnology 14:615-619) through complementary sequence
recognition or cleavage, as through ribozymes.
[0298] Telomerase activity can be inhibited by targeting mTERT
mRNA with antisense oligonucleotides capable of binding mTERT
mRNA. In some situations, naturally occurring nucleic acids used
as antisense oligonucleotides may need to be relatively long (18
to 40 nucleotides) and present at high concentrations, a wide
variety of synthetic, non-naturally occurring nucleotide and
nucleic acid analogues are known which can address this
potential problem. For example, peptide nucleic acids (PNAs)
containing non-ionic backbones, such as N-(2-aminoethyl) glycine
units can be used. PNAs targeting hTERC have been described, as
well as methods for internalizing such PNAs in cells. See, U.S.
Ser. No. 08/630,019, filed Apr. 9, 1996, and U.S. Ser. No.
08/838,545 and PCT/US/97/05931, filed on Apr. 9, 1997 (also, see
Norton (1996) supra). Antisense oligonucleotides having
phosphorothioate linkages can also be used, as described in WO
97/03211; WO 96/39154; Mata (1997) Toxicol Appl Pharmacol
144:189-197; Antisense Therapeutics, ed. Sudhir Agrawal (Humana
Press, Totowa, N.J., 1996). Antisense oligonucleotides having
synthetic DNA backbone analogues provided by the invention can
also include phosphorodithioate, methylphosphonate,
phosphoramidate, alkyl phosphotriester, sulfamate,
3'-thioacetal, methylene(methylimino), 3'-N-carbamate, and
morpholino carbamate nucleic acids, and other synthetic,
non-naturally occurring nucleotide and oligonucleotide mimetics.
[0299] As noted above, combinatorial chemistry methodology can
be used to create vast numbers of oligonucleotides that can be
rapidly screened for specific oligonucleotides that have
appropriate binding affinities and specificities toward any
target, such as the mTERT proteins of the invention, can be
utilized (see Gold (1995) J. of Biol. Chem. 270:13581-13584).
[0300] i. Inhibitory Ribozymes
[0301] Ribozymes act by binding to a target RNA through the
target RNA binding portion of a ribozyme which is held in close
proximity to an enzymatic portion of the ribozyme that cleaves
the target RNA. Thus, the ribozyme recognizes and binds a target
RNA through complementary base-pairing, and once bound to the
correct site, acts enzymatically to cleave and inactivate the
target RNA. Cleavage of a target RNA in such a manner will
destroy its ability to direct synthesis of an encoded protein if
the cleavage occurs in the coding sequence. After a ribozyme has
bound and cleaved its RNA target, it is typically released from
that RNA and so can bind and cleave new targets repeatedly.
[0302] In some circumstances, due to the enzymatic nature of a
ribozyme, ribozyme technology can be advantageous over other
technologies, such as antisense technology (where a nucleic acid
molecule simply binds to a nucleic acid target to block its
transcription, translation or association with another molecule)
as the effective concentration of ribozyme necessary to effect a
therapeutic treatment can be lower than that of an antisense
oligonucleotide. This potential advantage reflects the ability
of the ribozyme to act enzymatically. Thus, a single ribozyme
molecule is able to cleave many molecules of target RNA. In
addition, a ribozyme is typically a highly specific inhibitor,
with the specificity of inhibition depending not only on the
base pairing mechanism of binding, but also on the mechanism by
which the molecule inhibits the expression of the RNA to which
it binds. That is, the inhibition is caused by cleavage of the
RNA target, and so specificity is defined as the ratio of the
rate of cleavage of the targeted RNA over the rate of cleavage
of non-targeted RNA. This cleavage mechanism is dependent upon
factors additional to those involved in base pairing. Thus, the
specificity of action of a ribozyme can be greater than that of
an antisense oligonucleotide binding the same RNA site.
[0303] The enzymatic ribozyme RNA molecule has complementarity
to the target, such as the mRNA encoding mTERT. The enzymatic
ribozyme RNA molecule is able to cleave RNA and thereby
inactivate a target RNA molecule. The complementarity functions
to allow sufficient hybridization of the enzymatic ribozyme RNA
molecule to the target RNA for cleavage to occur. One hundred
percent complementarity is preferred, but complementarity as low
as 50-75% may also be employed. The present invention provides
ribozymes targeting any portion of the coding region for an
mTERT gene or gene product, i.e., any ribozyme that can cleave a
TERT mRNA or a TERT gene in a manner that will inhibit the
translation or transcription of the mRNA and thus reduce
telomerase activity. In addition, the invention provides
ribozymes targeting the nascent, unspliced RNA transcript of the
mTERT gene to reduce telomerase activity.
[0304] The enzymatic ribozyme RNA molecule can be formed in a
hammerhead motif, but may also be formed in the motif of a
hairpin, hepatitis delta virus, group I intron or RNaseP-like
RNA (in association with an RNA guide sequence). Examples of
such hammerhead motifs are described by Rossi (1992) Aids
Research and Human Retroviruses 8:183; hairpin motifs by Hampel
(1989) Biochemistry 28:4929, and Hampel (1990) Nuc. Acids Res.
18:299; the hepatitis delta virus motif by Perrotta (1992)
Biochemistry 31:16; the RNaseP motif by Guerrier-Takada (1983)
Cell 35:849; and the group I intron by Cech, et al., U.S. Pat.
No. 4,987,071. The recitation of these specific motifs is not
intended to be limiting; those skilled in the art will recognize
that an enzymatic RNA molecule of this invention has a specific
substrate binding site complementary to one or more of the
target gene RNA regions, and has nucleotide sequence within or
surrounding that substrate binding site which imparts an RNA
cleaving activity to the molecule.
[0305] ii. Delivery of mTERT
Inhibitory Oligonucleotides
[0306] The mTERT-inhibitory oligonucleotides of the invention
can be transferred into the cell using a variety of techniques
well known in the art. For example, oligonucleotides can be
delivered into the cytoplasm spontaneously, without specific
modification. Alternatively, they can be delivered by the use of
liposomes which fuse with the cellular membrane or are
endocytosed, i.e., by employing ligands attached to the
liposome, or attached directly to the oligonucleotide, that bind
to surface membrane protein receptors of the cell resulting in
endocytosis. For example, a DNA binding protein, e.g., HBGF-1,
is known to transport oligonucleotides into a cell. See, e.g.,
Tseng (1997) J. Biol. Chem. 272:25641-25647; Satoh (1997)
Biochem. Biophys. Res. Commun. 238:795-799, describing efficient
gene transduction by Epstein-Barr-virus-based vectors coupled
with cationic liposome and HVJ-liposome.
[0307] The procedures for delivering the oligonucleotides of the
invention to cells in vitro are useful in vivo. For example, by
using liposomes, particularly where the liposome surface carries
ligands specific for target cells, or arc otherwise
preferentially directed to a specific organ, one may provide for
the introduction of the oligonucleotides into the target cells
in vivo. See, e.g., Huwyler(1997) J. Pharmacol. Exp. Ther.
282:1541-1546, describing receptor mediated delivery using
immunoliposomes.
[0308] Alternatively, the cells may be permeabilized to enhance
transport of the oligonucleotides into the cell, without
injuring the host cells. See, e.g., Verspohl (1997) Cell.
Biochem. Funct. 15:127-134; Kang (1997) Pharm. Res. 14:706-712;
Bashford (1994) Methods Mol. Biol. 27:295-305, describing use of
bacterial toxins for membrane permeabilization; and for general
principles of membrane permeabilization, see Hapala (1997) Crit.
Rev. Biotechnol. 17:105-122.
[0309] e. Telomerase-associated
Proteins as Dominant Negative Mutants
[0310] In one embodiment of the invention, telomerase-associated
proteins are used as modulators of murine telomerase enzyme and
mTERT activity. Telomerase-associated proteins include
chromosomal structures, such as histones, nuclear matrix
protein, cell division/cell cycle control proteins and the like.
Other telomerase-associated proteins which can be used as
modulators for the purpose of the invention include p80, p95,
and human proteins, such as TP1 (Saito (1997) Genomics
46:46-50), TPC-2, TPC-3 (U.S. Ser. No. 08/710,249, filed Sep.
13, 1996) and PIN2 (Shen (1997) Proc. Natl. Acad. Sci. USA
94:13618-13623), TRF-1 and TRF-2 (Chong (1995) Science
270:1663-1667; Broccoli (1997) "Human telomeres contain two
distinct Myb-related proteins, TRF1 and TRF2," Nat. Genet.
17:231-235). In addition, TERT binding fragments of these
chromosomal telomerase-associated proteins can be identified by
the skilled artisan in accordance with the methods of the
invention and used as modulators of telomerase activity (see
also, e.g., Lauber (1997) J. Biol. Chem. 272:24657-24665, to
identify nuclear matrix DNA attachment sites).
[0311] i. Identifying
Telomerase-associated Proteins for Use as Modulators
[0312] In one embodiment of the invention, mTERT and
mTERT-containing telomerase enzyme are used to identify
telomerase-associated proteins, i.e., telomerase accessory
proteins which modulate or otherwise complement telomerase
activity. As noted above, these proteins or fragments thereof
can modulate function by causing the dissociation or prevention
the association of the telomerase enzyme complex, prevent the
assembly of the telomerase complex, prevent mTERT from binding
to its nucleic acid complement or to its DNA template, prevent
mTERT from binding nucleotides, or prevent, augment, or inhibit
any one, several or all of the partial activities of telomerase
enzyme or mTERT protein.
[0313] The skilled artisan can use a variety of well-known
techniques to identify telomerase-associated proteins, including
phage display (Katz (1997) Annu. Rev. Biophys. Biomol. Struct.
26:27-45), the two hybrid system (as in James (1996) Genetics
144:1425-1436; Adey (1997) Biochem. J. 324:523-528; Cowell
(1997) "Yeast two-hybrid library screening," Methods Mol. Biol.
69:185-202), and disease correlation. Other well-known
techniques include co-immunoprecipitation analysis, as used in
Zhao (1994) J. Biol. Chem. 269:15577-15582. Another well known
technique for isolating co-associating proteins involves the use
of chemical cross-linkers, including cleavable cross-linkers
dithiobis (succinimidylpropionate) and
3,3'-dithiobis(sulfosuccinimidyl-propionate); see e.g., Tang
(1996) Biochemistry 35:8216-8225. Photocross linking experiments
implicated a 123 kd protein in the specific binding of telomeric
DNA substrate in Euplotes aediculatus (Lingner (1996) Proc.
Natl. Aca. Sci. U.S.A. 93:10712).
[0314] ii. Dominant-negative
Mutants of mTERT
[0315] The present invention provides non-functional,
"dominant-negative" mTERT mutants. Dominant-negative mutant
forms of enzymes can be used to competitively substitute for
endogenous forms of the enzyme to affect the function, structure
(e.g., as as herterocomplex, a quaternary structure) location,
half-life, or compartmentalization of the enzyme. The invention
provides for mTERT telomerase mutant forms that can
competitively interfere with or replace wild-type (native) form
of mTERT. Such mutant mTERTs can, e.g., interfere with or
replace native mTERT in the formation of the telomerase enzyme
complex (i.e., mTERT with mTERC) or compete for mTERT-telomere
binding sites. In this manner, the effective amounts of
functional telomerase in the cell can be reduced or altered or a
new function or form of telomerase can be created. This can be
used, e.g., to have a therapeutic effect, by reducing the level
of telomerase activity in a cancer cell, to modulate telomere
length in a cell, study the consequence of a TERT mutation, or
to elucidate biological functions of a TERT or its mutants.
[0316] Mutations creating dominant-negative forms of mTERT can
be generated by, e.g., mutating any of the above-described TERT
motifs or other codons of the mTERT gene. For example, codons
for the conserved amino acid residues in each of any of the
conserved TERT motifs can be changed to other codons, resulting
in a variety of coding sequences which express a partially
non-functional mTERT. Eight highly conserved motifs have been
identified in TERTs of different species, including mouse and
man, see Lingner (1997) supra. FIG. 3 shows the alignment of
mTERT with hTERT, and positions of motifs are indicated. FIGS. 4
and 5 show mTERT motifs in relation to the sequence conservation
between mTERT and other TERTs: human, Euplotes aediculatus,
Saccharomyces cerevisiae, Schizosaccharomyces
pombe. Thus, the present invention provides a wide variety of
"mutated" telomerase enzymes and mTERT proteins which have a
partial activity but not full activity of telomerase enzyme.
[0317] For example, one such telomerase is able to bind
telomeric structures, but not bind telomerase-associated RNA
(i.e., mTERC). If expressed at high enough levels, such a
telomerase mutant can deplete a necessary telomerase component
(e.g., the telomere binding site) and thereby function as an
inhibitor of wild-type telomerase activity. A mutated telomerase
acting in this manner is as an antagonist or a so-called
"dominant negative" mutant.
[0318] Example 8 below describes three mutants of mTERT which
are predicted to be deficient in a telomerase activity. These
mutations change amino acids in the conserved RT motifs
previously shown to be essential for RT function (Lingner (1997)
supra). The predictions are based on similar results for
analogous mutations in hTERT (Weinrich (1997) supra). The
mutations are created using the procedures described in Weinrich
(1997) supra.
5. Definitions
[0319] To facilitate understanding the invention, a number of
terms are defined below.
[0320] The term "antibody" refers to a polypeptide substantially
encoded by an immunoglobulin gene or immunoglobulin genes, or
fragments or synthetic or recombinant analogues thereof which
specifically bind and recognize analytes and antigens. The
recognized immunoglobulin genes include the kappa, lambda,
alpha, gamma, delta, epsilon and mu constant region genes, as
well as myriad immunoglobulin variable region genes. Light
chains are classified as either kappa or lambda. Heavy chains
are classified as gamma, mu, alpha, delta, or epsilon, which in
turn define the immunoglobulin classes, IgG, IgM, IgA, IgD and
IgE, respectively. An exemplary immunoglobulin (antibody)
structural unit comprises a tetramer. Each tetramer is composed
of two identical pairs of polypeptide chains, each pair having
one "light" (about 25 kD) and one "heavy" chain (about 50-70
kD). The N-terminus of each chain defines a variable region of
about 100 to 110 or more amino acids primarily responsible for
antigen recognition. The terms variable light chain (VL) and
variable heavy chain (VH) refer to these light and heavy chains
respectively. Antibodies exist, e.g., as intact immunoglobulins
or as a number of well characterized fragments produced by
digestion with various peptidases, see, FUNDAMENTAL IMMUNOLOGY,
3RD ED., W. E. Paul, ed., Raven Press, N.Y. (1993). While
various antibody fragments are defined in terms of the digestion
of an intact antibody, one of skill will appreciate that such
fragments may be synthesized de novo either chemically or by
utilizing recombinant DNA methodologies, for example,
recombinant single chain Fv or antibodies or fragments thereof
displayed on the surface of a phage, virus or a cell. The term
"immunologically reactive conditions" refers to an environment
in which antibodies can bind to antigens, such as an mTERT of
the invention. As discussed below, this can be an immunological
binding assay. The phrase "specifically binds to an antibody"
when referring to a protein or peptide, refers to a binding
reaction which is determinative of the presence of the protein
in the presence of a heterogeneous population of proteins and
other biologics. Thus, under designated immunoassay conditions,
the specified antibodies bind to a particular protein and do not
bind in a significant amount to other proteins present in the
sample. Specific binding to an antibody under such conditions
may require an antibody that is selected for its specificity for
a particular protein. For example, antibodies specific for the
mTERT protein of this invention or to any portion or the protein
defined by the sequence of SEQ ID NO:2 can be selected to
immunoreact specifically with all murine mTERT species of the
invention or only a single mTERT specie (an allele, homologue,
or isoform), and not with non-mouse TERT proteins or
non-telomerase proteins. As described below, a variety of
immunoassay formats may be used to select antibodies
specifically immunoreactive with a particular protein, such as
mTERT. For example, solid-phase ELISA immunoassays are routinely
used to select monoclonal antibodies specifically immunoreactive
with mTERT. See Harlow and Lane, supra, for a description of
immunoassay formats and conditions that can be used to determine
specific immunoreactivity, a specific or selective reaction is
one which generates a signal at least twice (2*) over background
signal or "noise."
[0321] The term "buffered aqueous solution compatible with
telomerase activity" refers to conditions suitable for in vitro
reactions, such as in vitro transcription and translation
reactions, or activity assays, i.e., compatible physiological
conditions. The term refers to temperature, pH, ionic strength,
viscosity, and like biochemical parameters which can be
compatible with a telomerase enzyme or mTERT activity, full or
partial, e.g., such as those conditions that exist in a viable
organism, e.g. conditions which typically exist intracellularly
in a viable cultured eukaryotic cell, such as a yeast or a
mammalian cell. Compatible physiologic conditions for mTERT and
telomerase enzyme activity (conditions suitable for in vitro
reactions), however, can be substantially different from
conditions which typically exist intracellularly. For example,
the intracellular conditions in a yeast cell grown under typical
laboratory culture conditions are considered physiological
conditions. In general, in vitro physiological conditions
comprise 50-200 mM NaCl or KCl, pH 6.5-8.5, 20-45 EC and
0.001-10 mM divalent cation (e.g., Mg<++> , Ca<++>
), preferably about 150 mM NaCl or KCl, pH 7.2-7.6, 5 mM
divalent cation, and often include 0.01-1.0 percent nonspecific
protein (e.g., BSA). In addition, a non-ionic detergent (Tween,
NP40, Triton X-100) can often be present, usually at about 0.001
to 2%, typically 0.05-0.2% (v/v). Particular aqueous conditions
may be selected by the practitioner according to conventional
methods. For general guidance, the following buffered aqueous
conditions can be applicable: 10-250 mM NaCl, 5-50 mM Tris HCl,
pH 5-8, with optional addition of divalent cation(s) and/or:
metal chelators; nonionic detergents; membrane fractions;
antifoam agents; and/or scintillants.
[0322] The term "conservative substitution" refers to a change
in the amino acid composition of a protein, such as the mTERT of
the invention, that does not substantially alter the protein's
activity. This includes conservatively substituted variations of
a particular amino acid sequence, ie., amino acid substitutions
of those amino acids that are not critical for protein activity
or substitution of amino acids with other amino acids having
similar properties (e.g., acidic, basic, positively or
negatively charged, polar or non-polar, etc.) such that the
substitutions of even critical amino acids do not substantially
alter activity. Conservative substitution tables providing
functionally similar amino acids are well known in the art. The
following six groups each contain amino acids that are
conservative substitutions for one another: 1) Alanine (a),
Serine (S), Threonine (T); 2) Aspartic acid (D), Glutamic acid
(E); 3) Asparagine (N), Glutaine (Q); 4) Arginine (R), Lysine
(K); 5) Isoleucine (1), Leucine (L), Methionine (M), Valine (V);
and 6) Phenylalanine (F), Tyrosine (Y), Tryptophan (W) (see
also, Creighton (1984) Proteins, W.H. Freeman and Company). One
of skill in the art will appreciate that the above-identified
substitutions are not the only possible conservative
substitutions. For example, for some purposes, one may regard
all charged amino acids as conservative substitutions for each
other whether they are positive or negative. In addition,
individual substitutions, deletions or additions which alter,
add or delete a single amino acid or a small percentage of amino
acids in an encoded sequence can also be considered
"conservatively substituted variations." The term "conservative
substitution" also refers to a change in a nucleic acid sequence
such that the substitution does not substantially alter the
contemplated activity of the nucleic acid, for example, as not
changing the activity of the protein encoded by the nucleic
acid, a nucleic acid sequence of the invention implicitly
encompasses conservatively modified variants thereof (e.g.
degenerate codon substitutions) and complementary sequences and
not just the sequence explicitly indicated. Specifically,
degenerate codon substitutions may be achieved by generating
sequences in which the third position of one or more selected
(or all) codons is substituted with mixed-base and/or
deoxyinosine residues (Batzer (1991) Nucleic Acid Res. 19:5081;
Ohtsuka (1985) J. Biol. Chem. 260:2605-2608; Rossolini (1994)
Mol. Cell. Probes 8:91-98).
[0323] The term "expression vector" refers to any recombinant
expression system for the purpose of expressing a nucleic acid
sequence of the invention, as SEQ ID NO:1, in vitro or in vivo,
constitutively or inducibly, in any cell, including prokaryotic,
yeast, fungal, plant, insect or mammalian cells. The term
includes linear or circular expression vectors. The term
includes expression vectors that remain episomal or integrate
into the host cell genome. The expression vectors can have the
ability to self-replicate or not, i.e., drive only transient
expression in a cell. The term includes recombinant expression
vector "cassettes" which contain only the minimum elements
needed for transcription of the recombinant nucleic acid. See,
e.g., Arnaud (1997) Genex 199:149-156.
[0324] A "fusion protein" refers to a composition comprising at
least one polypeptide or peptide domain which is associated with
a second typically polypeptide or peptide domain. The
polypeptide or peptide domain can comprise an mTERT or
subsequence thereof. The second domain can be a polypeptide,
peptide, polysaccharide, polynucleotide, or the like. The
"fusion" can be an association generated by a chemical linking
or by a charge (electrostatic attraction, i.e., salt bridges,
H-bonding, etc.) interaction. If the polypeptides are
recombinant, the "fusion protein" can be translated from a
common message. Alternatively, the compositions of the domains
can be linked by any chemical or electrostatic means. The
invention includes compositions which are "fusion proteins"
comprising mTERT and non-mTERT (exogenous) polypeptide sequences
or compositions to aid in cell targeting, purification,
expression and/or detection of mTERT and murine telomerase
enzyme.
[0325] The terms "isoform," "allele," and "homologue" refer to a
nucleic acid or polypeptide mTERT specie. The nucleic acid or
protein can be considered an mTERT isoform, homologue or allele
if it shares at least 40 percent to 50 percent sequence identity
to any known mTERT specie, including but not limited to the
mTERT identified by SEQ ID NO:1 or SEQ ID NO:2, respectively.
[0326] As used herein, "isolated," when referring to a molecule
or composition, such as, e.g., an mTERT or a
telomerase-associated nucleic acid or polypeptide, means that
the molecule or composition is separated from at least one other
compound, such as a protein, other nucleic acids (e.g., RNAs),
or other contaminants with which it is associated in vivo or in
its naturally occurring state. Thus, an mTERT is considered
isolated when the mTERT has been isolated from any other
component with which it is naturally associated, e.g., cell
membrane, as in a cell extract. An isolated composition can,
however, also be substantially pure. An isolated composition can
be in a homogeneous state and can be in a dry or an aqueous
solution. Purity and homogeneity can be determined, for example,
using analytical chemistry techniques such as polyacrylamide gel
electrophoresis (SDS-PAGE) or high performance liquid
chromatography (HPLC).
[0327] The term "label" refers to a detectable composition, such
as by spectroscopic, photochemical, biochemical, immunochemical,
physical or chemical means. For example, useful labels include
<32> P, <35> S, <3> H, <14> C,
<125> I, <131> I, fluorescent dyes (e.g., FITC,
rhodamine, lanthanide phosphors), electron-dense reagents,
enzymes, e.g. as commonly used in an ELISA (e.g., horseradish
peroxidase, beta-galactosidase, luciferase, alkaline
phosphatase), biotin, dioxigenin, or haptens and proteins for
which antisera or monoclonal antibodies are available. The label
can be directly incorporated into the nucleic acid, peptide or
other target compound to be detected, or it can be attached to a
probe or antibody which hybridizes or binds to the target, a
peptide can be made detectable by incorporating predetermined
polypeptide epitopes recognized by a secondary reporter (e.g.,
leucine zipper pair sequences, binding sites for secondary
antibodies, transcriptional activator polypeptide, metal binding
domains, epitope tags). In some embodiments, labels are attached
by spacer arms of various lengths to reduce potential steric
hindrance or impact on other useful or desired properties. See
e.g., Mansfield (1995) Mol. Cell Probes 9:145-156.
[0328] The term "modulator" refers to any synthetic or natural
compound or composition that can change in any way either the
"full" or any "partial activity" of a TERT or a telomerase
enzyme, a modulator can be an agonist or an antagonist, a
modulator can be, but is not limited to, any organic and
inorganic compound; including, e.g., small molecules, peptides,
proteins, sugars, nucleic acids, fatty acids and the like.
[0329] The term "murine" refers to any and all members of the
family Muridae, including rats and mice. As used herein, the
term "mouse" and "mice" encompass all members of the family
Muridae. Thus, the term "mTERT," as defined below, "murine TERT"
and "mouse TERT" are equivalent and encompass TERT species from
all members of the family Muridae.
[0330] The term "nucleic acid molecule" or "nucleic acid
sequence" refers to a deoxyribonucleotide or ribonucleotide
oligonucleotide in either single- or double-stranded form. The
term encompasses nucleic acids, i.e., oligonucleotides,
containing known analogues of natural nucleotides which have
similar or improved binding or other properties, for the
purposes desired, as the reference nucleic acid. The term also
includes nucleic acids which are metabolized in a manner similar
to naturally occurring nucleotides or at rates that are improved
thereover for the purposes desired. The term also encompasses
nucleic-acid-like structures with synthetic backbones. DNA
backbone analogues provided by the invention include
phosphodiester, phosphorothioate, phosphorodithioate,
methyl-phosphonate, phosphoramidate, alkyl phosphotriester,
sulfamate, 3'-thioacetal, methylene (methylimino),
3'-N-carbamate, morpholino carbamate, and peptide nucleic acids
(PNAs); see Oligonucleotides and Analogues, a Practical
Approach, edited by F. Eckstein, IRL Press at Oxford University
Press (1991); Antisense Strategies, Annals of the New York
Academy of Sciences, Volume 600, Eds. Baserga and Denhardt (NYAS
1992); Milligan (1993) J. Med. Chem. 36:1923-1937; Antisense
Research and Applications (1993, CRC Press) in its entirety and
specifically Chapter 15, by Sanghvi, entitled "Heterocyclic base
modifications in nucleic acids and their applications in
antisense oligonucleotides." PNAs contain non-ionic backbones,
such as N-(2-aminoethyl) glycine units, as described in U.S.
Ser. No. 08/630,019, filed 9 Apr. 1996, and the US CIP U.S. Ser.
No. 08/838,545 and PCT application PCT/US/97/0593 1, both filed
on Apr. 9, 1997. Phosphorothioate linkages are described in WO
97/03211; WO 96/39154; Mata (1997) Toxicol Appl Pharmacol
144:189-197. Other synthetic backbones encompassed by the term
include, e.g., methylphosphonate linkages or alternating
methylphosphonate and phosphodiester linkages (Strauss-Soukup
(1997) Biochemistry 36:8692-8698), and benzylphosphonate
linkages, which, when compared with unmodified oligonucleotides
and methylphosphonates, are more stable against nucleases and
exhibit a higher lipophilicity (Samstag (1996) Antisense Nucleic
Acid Drug Dev 6:153-156). The term nucleic acid is used
interchangeably with gene, cDNA, mRNA, oligonucleotide primer,
probe and amplification product. The terms "exogenous nucleic
acid" and "heterologous nucleic acid" refer to a nucleic acid
that has been isolated, synthesized, cloned, ligated, excised in
conjunction with another nucleic acid, in a manner that is not
found in nature, and/or introduced into and/or expressed in a
cell or cellular environment other than or at levels or forms
different than the cell or cellular environment in which said
nucleic acid or protein is found in nature. The term encompasses
both nucleic acids originally obtained from a different organism
or cell type than the cell type in which it is expressed and
also nucleic acids that are obtained from the same cell line as
the cell line in which it is expressed.
[0331] The term "recombinant," when used with reference to a
cell, or to a nucleic acid, protein or vector, refers to a
material or a material corresponding to the natural or native
form of the material, that has been modified by the introduction
of a new moiety or alteration of an existing moiety, or is
identical thereto but produced or derived from synthetic
materials. For example, recombinant cells express genes that are
not found within the native (non-recombinant) form of the cell
or express native genes or gene products that are otherwise
expressed at a different level, typically, under-expressed or
not expressed at all. The term "recombinant means" encompasses
all means of expressing, ie., transcription or translation of an
isolated and/or cloned nucleic acid in vitro or in vivo. For
example, the term "recombinant means" encompasses techniques
where a recombinant nucleic acid, such as a cDNA encoding a
protein, is inserted into an expression vector (including
"expression cassettes"), the vector is introduced into a cell,
i.e., the cell is "transfected" or "transformed" and the cell
expresses the protein. "Recombinant means" also encompass the
ligation of nucleic acids having coding or transcriptional
regulatory (e.g., promoter) sequences from different sources
into one expression cassette or vector for expression of a
fusion protein, constitutive expression of a protein, or
inducible expression of a protein, such as the mTERT protein of
the invention.
[0332] The terms "homology," "sequence identity" and "sequence
similarity" refers to a degree of complementarity or sequence
identity. There may be partial homology or complete homology
(ie., identity), a partially complementary sequence is one that
at least partially inhibits a completely complementary sequence
from hybridizing to a target nucleic acid and can be referred to
using the functional term as "substantially homologous" to the
completely complementary sequence. The inhibition of
hybridization of the completely complementary sequence to the
target sequence may be examined using a hybridization assay
(Southern or Northern blot, solution hybridization and the like)
under conditions of low stringency, a substantially homologous
sequence or probe will compete for and inhibit the binding
(i.e., the hybridization) of a completely homologous nucleic
acid to a target nucleic acid under conditions of low
stringency. This is not to say that conditions of low stringency
are such that non-specific binding is permitted; low stringency
conditions require that the binding of two sequences to one
another be a specific (ie., selective) interaction. The absence
of non-specific binding may be tested by the use of a second
target which lacks even a partial degree of complementarity; in
the complete absence of non-specific binding the probe will not
hybridize to the second non-complementary target. The terms
"sequence identity," "sequence similarity" and "homology" refer
to two or more sequences, such as the diverse nucleic acid and
amino acid sequences of the mTERT proteins of the telomerase of
the invention, that, when optimally aligned, as with the
programs BLAST, GAP, FASTA or BESTFIT, share at least 40 percent
to 50 percent sequence identity, and preferably at least 60
percent or greater sequence identity. "Percentage amino acid
sequence identity" refers to a comparison of the sequences of
two TERT nucleic acids or polypeptides which, when optimally
aligned, have approximately the designated percentage of the
same nucleotides or amino acids, respectively. For example, "60%
sequence identity" and "60% homology" refer to a comparison of
the sequences of two nucleic acids or polypeptides which, when
optimally aligned, have 60% identity.
[0333] The term "an mTERT" polypeptide comprising an amino acid
sequence with significant sequence identity to a motif refers to
mTERT proteins which are considered to have a statistically
significant sequence identity, ie., have significant homology or
be significantly identical, at the amino acid sequence level in
a conserved region of a TERT protein, such as the motif
sequences defined herein. Two TERT proteins are considered to
have a statistically significant sequence identity in the
conserved region if, after adjusting for deletions, additions
and the like, the conserved regions have at least out 20% to 30%
sequence identity or greater sequence identity, preferably
higher, for example, about 40% to 50% or higher (ie., 80% to
90%) if the region of comparison is shorter, ie., a region of
about ten consecutive amino acids.
[0334] The terms "stringent hybridization," "stringent
conditions," or "specific hybridization conditions" refer to
conditions under which an oligonucleotide (when used, for
example, as a probe or primer) will hybridize to its target
subsequence, such as an mTERT sequence of a nucleic acid in an
expression vector of the invention but not to a non-telomerase
sequence. Stringent conditions are sequence-dependent. Thus, in
one set of stringent conditions an oligonucleotide probe will
hybridize to only one specie mTERT of the invention. In another
set of stringent conditions (less stringent) an oligonucleotide
probe will hybridize to all species of mTERT but not to
non-telomerase nucleic acids. Longer sequences hybridize
specifically at higher temperatures. Stringent conditions are
selected to be about 5[deg.] C. lower than the thermal melting
point (Tm) for the specific sequence at a defined ionic strength
and pH. The Tm is the temperature (under defined ionic strength,
pH, and nucleic acid concentration) at which 50% of the probes
complementary to the target sequence hybridize to the target
sequence at equilibrium (if the target sequences are present in
excess, at Tm, 50% of the probes are occupied at equilibrium).
Typically, stringent conditions will be those in which the salt
concentration is less than about 1.0 M sodium ion, ie., about
0.01 to 1.0 M sodium ion concentration (or other salts) at pH
7.0 to 8.3 and the temperature is at least about 30[deg.] C. for
short probes (e.g., 10 to 50 nucleotides) and at least about
60[deg.] C. for long probes (e.g., greater than 50 nucleotides).
Stringent conditions may also be achieved with the addition of
destabilizing agents such as formamide. Often, high stringency
wash conditions are preceded by low stringency wash conditions
to remove background probe signal. An example of medium
stringency wash conditions for a duplex of, e.g., more than 100
nucleotides, is 1*SSC at 45[deg.] C. for 15 minutes (see
Sambrook for a description of SSC buffer). An example of a low
stringency wash for a duplex of, e.g., more than 100
nucleotides, is 4-6*SSC at 40[deg.] C. for 15 minutes, a signal
to noise ratio of 2* (or higher) than that observed for an
unrelated probe in the particular hybridization assay indicates
detection of a "specific hybridization." Nucleic acids which do
not hybridize to each other under stringent conditions can still
be substantially identical if the polypeptides which they encode
are substantially identical. This can occur, e.g., when a
nucleic acid is created that encodes for conservative
substitutions. Stringent hybridization and stringent
hybridization wash conditions are different under different
environmental parameters, such as for Southern and Northern
hybridizations. An extensive guide to the hybridization of
nucleic acids is found in Tijssen (1993) supra.
[0335] The term "subsequence" refers to a sequence of a nucleic
acid or protein or an amino acid that comprises a part of a
longer sequence of a nucleic acid or a protein (e.g.,
polypeptide), respectively.
[0336] The term "test compound" refers to any synthetic or
natural compound or composition. The term includes all organic
and inorganic compounds; including, for example, small
molecules, peptides, proteins, sugars, nucleic acids, fatty
acids and the like.
[0337] The terms "transformed cell" and "transfected cell"
refers to any cell into which a heterologous or exogenous
nucleic acid has been inserted, either transiently or stably, by
recombinant means, i.e., by human intervention.
[0338] The terms "TERT" and "telomerase reverse transcriptase"
refer to a telomere-specific RNA-dependent DNA polymerase
protein, the telomerase holoenzyme without an RNA component, the
catalytic subunit of the telomerase enzyme complex. The term
"telomerase," "telomerase enzyme" and "telomerase enzyme
complex" refers to a TERT with at least one RNA component, i.e.,
an RNA moiety used as a template for DNA synthesis. The
telomerase enzyme can also include other telomerase-associated
compositions. The telomerase can utilize a portion of its RNA
moiety as a template to specify the addition of telomeric DNA
repeat sequences to chromosomal ends. The term "mTERT" and
"murine TERT" refer to murine TERT nucleic acids and proteins
with common structural and functional characteristics. mTERT
nucleic acids can be characterized as an mTERT protein having a
calculated molecular weight of between about 50 and 150 kDa and
specifically binding to an antibody raised against a protein
having a sequence of amino acids as in SEQ ID NO:2 or a
subsequence thereof or having at least 60% amino acid sequence
identity to a protein having a sequence of amino acids as in SEQ
ID NO:2. mTERT nucleic acids also comprise nucleic acids which
specifically hybridize to SEQ ID NO:1 under stringent
conditions, and nucleic acids encoding a protein which
specifically binds to an antibody directed against an mTERT
protein having a sequence of amino acids as in SEQ ID NO:2.
mTERT proteins can be characterized as having a calculated
molecular weight of about 50 to 150 kDa and specifically binding
to an antibody raised against a mTERT protein having a sequence
of amino acids as in SEQ ID NO:2 or subsequence thereof or
having 60% amino acid sequence identity to a mTERT protein
having a sequence of amino acids as in SEQ ID NO:2. Isolated or
recombinant mTERT proteins within the scope of the claimed
invention encompass murine proteins comprising species with
common structural characteristics, i.e., motifs, as discussed in
detail herein. The mTERTs of the invention include: species
capable of catalyzing the synthesis of telomeres when associated
with an RNA moiety, such as mTERC or hTERC; species capable of
one or several or all partial activities of mTERT and telomerase
enzyme; and species such as mTERT isoforms, homologues, and
alleles which are considered mTERT species of the invention
because they contain requisite common structural mTERT
characteristics (i.e., TERT motifs) or sufficient sequence
identity with any other mTERT specie. mTERT species include
mTERT from all murine or Muridae family species, including mice
and rats, as defined above. The term "an endogenous mTERT gene
which has been mutated by recombinant means" refers to a gene
which has been altered by a change in coding or non-coding,
transcribed or untranscribed, or mTERT transcriptional
regulatory sequences. If such a mutated gene is in a cell that
is placed in an animal, the resultant transgenic non-human
animal can be referred to as an "mTERT knockout" cell or animal,
as described, supra.
[0339] The terms "telomerase activity" and "telomerase reverse
transcriptase activity" ("TERT activity") can refer to either
"full" or any "partial activity" of a TERT or telomerase enzyme.
TERT activity includes the ability to synthesize DNA, such as a
telomere or telomeric DNA, using a nucleic acid template, such
as the telomerase RNA, a TERT "partial activity" can include,
but is not limited to, such functions as the ability of TERT to:
bind substrate DNA; bind a telomerase RNA moiety, i.e., mTERC or
hTERC; catalyze the addition of nucleotides to a DNA substrate;
bind deoxynucleotide substrate; exhibit "nucleolytic activity"
(see Collins (1993) Genes Dev 7:1364-1376); bind
telomere-associated proteins or chromosomal structures; exhibit
the "processive" or "non-processive" activity of telomerase (see
Morin (1989) supra); exhibit "reverse-transcriptase-like
activity" of telomerase (see Lingner (1997) supra); bind
nucleotides as part of its processive enzymatic DNA
polymerization activity; bind chromosomes in vivo; bind
oligonucleotide primers in vitro (Harrington (1995) J Biol Chem
270: 8893-8901) or in reconstituted systems; and bind histones,
nuclear matrix protein, cell division/cell cycle control
proteins and the like.
[0340] The examples and embodiments described herein are for
illustrative purposes only, and various modifications or changes
in light thereof will be suggested to persons skilled in the art
and thereby are to be included within the spirit and purview of
this disclosure and scope of the appended claims.
EXAMPLES
[0341] The following examples are offered to illustrate, but not
limit the claimed invention.
Example 1
Isolating, Cloning and
Sequencing mTERT cDNA and Genomic DNA
[0342] The following example details the isolation, cloning and
sequencing of mTERT cDNA and mTERT genomic DNA, including
transcriptional control elements and intronic sequences.
[0343] Mouse cDNA and genomic clones of TERT are provided by the
invention to, e.g., construct homozygous or heterozygous
deletions or other modifications of mTERT (i.e., deletions in
either one or both alleles), e.g., as in mTERT "knockout" cells
or mice; construct recombinant nucleic acids encoding mTERT
proteins differing in amino acid sequence at one or more
positions relative to native mTERT; characterize mTERT
biochemistry and biology; identify and isolate additional mTERT
species (alleles, isoforms, homologues); express mTERT and mTERC
or mTERT and hTERC in "knockout" animals, e.g., those unable to
express endogenous TERT or telomerase enzyme; express mTERT and
mTERC or hTERC in cell-free transcription/translation systems;
and express mTERT in cells or organisms which have retained the
ability to express endogenous telomerase and/or mTERC.
[0344] General Techniques for
Cloning of mTERT cDNA and Genomic Sequences
[0345] To obtain a clone of an mTERT, a hybridization step is
typically performed, a probe is constructed from a known mTERT
provided by the invention, such as the nucleic acid sequence set
forth in SEQ ID NO:1, or a TERT from another organism, such as
hTERT. The probe can be synthetically generated or it can be
generated by PCR. The probe can incorporate a synthetic
fragment, a PCR fragment or a restriction fragment(s) of a
nucleic acid comprising all or pat of the TERT gene or the TERT
coding sequence, which is then hybridized to DNA or RNA from the
target mouse cell.
[0346] The mouse DNA can be genomic DNA, a genomic DNA library,
RNA, cDNA, a cDNA library, or other sources of nucleic acid. In
one embodiment, a mouse cDNA library is screened to obtain a
fragment of mTERT cDNA. This fragment or its sequence can be
further used to identify a genomic clone or additional cDNA
clones. Use of cDNA may have advantages in that it is typically
free of introns. The source of the cDNA library is important; it
is preferably from a tissue known to possess telomerase activity
or TERT RNA. An embryonic stem cell cDNA library is a preferred
source of mTERT mRNA, as telomerase enzyme is expressed in stem
cells.
[0347] The invention provides TERT sequence-containing probes
useful for such screening, including the full length mTERT cDNA
(SEQ ID NO:1) and various fragments of mTERT cDNA. One such
probe includes a portion of TERT encompassing approximately the
first third of a TERT cDNA, such as the first third of mTERT
(SEQ ID NO:1). This region is more GC rich than the rest of the
protein and may be preferred for detecting additional mTERT
species in some circumstances. Thus, one embodiment uses this
subfragment of mTERT, or, analogously, the first third of hTERT,
or any other known TERT, as probes in screening for additional
species.
[0348] Another embodiment provides for a probe including a
portion of TERT encompassing approximately the middle third of a
TERT cDNA, such as mTERT cDNA (SEQ ID NO:1). This region encodes
a subset of the RT motifs and is likely to be the most conserved
region and so is preferred in some circumstances. Thus, a
preferred embodiment uses this subfragment of mTERT, or,
analogously, the middle third of hTERT, or any other known TERT,
as probes in screening for additional species.
[0349] An additional embodiment provides for a probe that is a
portion of TERT encompassing approximately the last third of a
TERT cDNA, such as the mTERT cDNA (SEQ ID NO:1). An alternative
embodiment uses this subfragment of TERT, or, analogously, the
last third of hTERT, or any other known TERT, as probes in
screening.
[0350] The screen can be performed with a mixture of the probes
to ensure the detection of at least one clone. Once a clone is
identified, it can be screened with each probe independently to
identify the region it encompasses. Then, the probes can be used
independently to find missing regions, if any. When an mTERT is
identified, a screen of a mouse genomic library can be performed
using the mTERT clone as a probe. If the initial hybridization
uses a non-mouse probe, such as hTERT, it can be performed at
reduced stringency. As isoforms, homologues, and alleles of
mTERT genes are expected to be about 60-95% identical to other
TERTs, such as hTERT, appropriate hybridization conditions can
be readily calculated, see e.g., Sambrook.
[0351] The mouse genomic clone and genomic sequences can be
used, e.g, to prepare constructs for making transgenic mice
expressing TERT. The mTERT constructs of the invention can be
used to create an mTERT knockout cell or mouse by homologous
recombination, as discussed herein in relation to knockout
procedures. To clone an entire genomic mTERT, multiple large
genomic lambda clones can be used to span the entire mouse
genomic sequence.
[0352] In one embodiment, a mouse ES library is used to identify
a mouse TERT-encoding nucleic acid clone, a preferred library is
the Mouse Embryonic Stem Cell 5'-STRETCH cDNA library, cat #
ML1049a, Clontech, Palo Alto, Calif., average insert size 1.6 Kb
(0.8-4.5 Kb range), vector=1gt10, oligo dT and random hexamer
primed with EcoRI linkers, RNA source=D3 cell line (pluripotent
ES cells) (Doetschman (1985) J. Embryol. Exp. Morphol.
87:27-45).
[0353] Cloning of the m TERT
cDNA and mTERT Genomic Nucleic Acid
[0354] A conventionally constructed mouse embryonal stem cell
cDNA lambda gt10 phage library (Clontech, Palo Alto, Calif.) was
screened using three human hTERT nucleic acid probes. The probes
were designated A, B, and C, each approximately the same size,
encompassing almost the entire hTERT coding region, running 5'
to 3', respectively. These probes were derived from the
hTERT-containing plasmid pGRN121, ATCC Accession No. ATCC209016,
deposited May 6, 1997, and described in U.S. Ser. No.
08/915,503, U.S. Ser. No. 08/912,951, and, U.S. Ser. No.
08/911,312, all filed Aug. 14, 1997; and in U.S. Ser. No.
08/974,549, and U.S. Ser. No. 08/974,584, both filed on Nov. 19,
1997. Probe A is an Eco47111/Eco47111, 1203 base pair long
fragment encompassing residues 729 to 1932 of pGRN121; probe B
is a Sph1/Xmn1, 1143 base pair long fragment encompassing
residues 2278 to 3421 of pGRN121; and probe C is an Xmn1/Msc1,
760 base pair long fragment encompassing residues 3421 to 4181
of pGRN121. The probes were hybridized using a conventional, low
stringency hybridization protocol, with prehybridization and
hybridization solutions containing 35% formamide at 37[deg.] C.
for 12 hours.
[0355] A recombinant phage cDNA clone which specifically
hybridized to the hTERT probe was isolated. A TERT-encoding 2 kb
long nucleic acid insert was isolated, subcloned into a plasmid,
and sequenced. The plasmid with this insert is designated
pGRN227. Analysis of this sequence, including its comparison to
known TERT sequences, was performed. The analysis determined
that the insert possessed extensive sequence homology with
hTERT, matching about 70% of the DNA sequence of hTERT around
positions 1870 to 2150 of plasmid pGRN121. The 2 kb insert was
2006 base pairs long. Sequence analysis indicated that it
included 1977 base pairs of mTERT coding sequence, which is
about half the mTERT protein's open reading frame. The insert
included some 5' non-coding sequence and sufficient coding (open
reading frame, or ORF) sequence to identify the TERT motifs 1
and 2, which, based on related TERT sequences, was determined to
be about half of the ORF for the mTERT protein.
[0356] To isolate the remaining coding sequence, a PCR
amplification reaction was carried out using cDNA prepared from
mouse testis polyA+ mRNA (Clontech, Palo Alto, Calif.). PCR
amplification primers were designed: the primer pair included a
5' primer with sequence from the above-described 2 kb insert
(called mTRT.9) (5'-CTTTTACATCACAGAGAGCAC-3') (SEQ ID NO:15) and
a 3' primer from a conserved region of hTERT (called hTRT.28)
(5'-CTCGGACCAGGGTCCTGAGGAA-3') (SEQ ID NO:8), a conventional
RT-PCR protocol was used. The resultant amplified segment was
subcloned into a plasmid and sequenced. The plasmid with this
insert is called mTRT Ra3' (pGRN230). Analysis of the sequence
showed that this cDNA insert included further coding sequence of
mTERT, including new coding sequence 3' to the initially
characterized 2 kb segment. Analysis of this cDNA sequence
indicated that this second amplification product included TERT
motifs T, 1, 2, A, B', and C. This amplified sequence did not
include the entire mTERT coding sequence. Approximately 800 base
pairs of coding sequence and the 3' untranslated region remained
to be isolated.
[0357] To isolate the remaining 3' end of the mTERT sequence,
bacterial artificial chromosomes (BAC clones) containing genomic
mouse DNA were screened by Southern hybridization using probes
designed from hTERT, as described above. Conventional, low
stringency hybridization protocols were used, together with the
probes designated A, B and C, described above, a clone that
positively hybridized to probe C, under selective conditions,
was isolated. Genomic BAC clones (BAC 495-M5 and 145 K20) were
isolated and the inserts subcloned as Pst1 fragments (called
mTRT Pst1, mTRT Pst3, and mTRT 496-2A2). Sequence analysis of
these clones indicated that they included the 3' one third of
the mTERT coding sequence, including the 3' untranslated region
(UTR). These inserts also were found to include mTERT intronic
sequence (as noted above, the insert was derived from genomic
BAC clones).
[0358] A RT-PCR product (called mTRT Ra-200) from the cDNA
described above was obtained using primers mTRT.35 (from mTRT
Ra3') (5'-CTTCCTCAGGACCCTGGTCCGAG-3') (SEQ ID NO:9) and mTRT.27
(from mTRT 495-2A2) (5'-ATTGAGGTCTGGGCATACCTGC-3') (SEQ ID
NO:10). This reaction amplified a contaminating DNA encoding a
portion of the mTERT gene and a non-coding region.
[0359] Another DNA containing the 3' end of the mTERT cDNA was
obtained by RT-PCR The primer pair was a 3' primer including the
sequence encoding the carboxy-terminus of hTERT cDNA
(5'-TCAGCGTCGTCCCCGGGAGCTT-3') (SEQ ID NO:11) and a 5' primer
from the above-described upstream mTERT amplification product
(mTRT Ra-200) (5'-TCACCCTCTGAGGCTTCGGTGT-3') (SEQ ID NO:12).
These two primers were reacted with cDNA from mouse poly
A<+> RNA. The product of this amplification was subcloned
(into plasmid designated mTRT Ra-62) and sequenced. Analysis of
the sequence showed that it included the carboxy-terminus
encoding portion of the ORF and 3' UTR (from the transcribed,
but untranslated cDNA sequence) and intronic sequences.
[0360] To construct a DNA spanning from pGRN227 to the 3' UTR,
cDNA from mouse testis poly A+ mRNA (Clontech, Palo Alto,
Calif.) was amplified using error-free, Pwo DNA polymerase
(Boehringer Mannheim, Amersterdam, The Netherlands). cDNA was
first made using a 3' oligo-dT primer in a 3' RACE amplification
protocol, as generally described above. Subsequently, the
primers mTRT.10 (5'-CGTCGATACTGGCAGATGCGG-3') (SEQ ID NO:13) and
mTRT.53 (5'-GTGCTGAGGCTACAATGCCCATGT-3') (SEQ ID NO:14) were
amplified at 94[deg.] C. for 30 min., 68[deg.] C. for 3 min.,
for 30 cycles; followed by 30 more cycles using primers mTRT.9
(5'-CTTTTACATCACAGAGAGCAC-3') (SEQ ID NO:15) and mTRT.52
(5'-CATGTTCATCTAGCGGAAGGAGACA-3') (SEQ ID NO:16). The PCR
product (called mTRT Ra-52) was cloned into pCR II (Invitrogen,
San Diego,CA), and 5 independent clones were isolated and the
mTERT inserts sequenced (called mTRT Ra52). The DNA insert
sequence was identical for all 5 clones and matched the sequence
of the mTERT PCR amplification products described above,
including the entire mTERT open reading frame. A unique NheI
restriction site located in the region of the overlap between
this RT-PCR product (called mTRT Ra 52.17 or pGRN189) and the 5'
mTERT cDNA clone was utilized to construct the full length mTERT
ORF. The plasmid with this fill-length ORF was designated
pGRN18. The mTERT insert of pGRN188 (SEQ ID NO:1) has been
submitted to Genbank as Accession No. AF051911 (and is
incorporated by reference herein, as noted below).
[0361] FIG. 1 shows the complete sequence of the mTERT cDNA (SEQ
ID NO:1). FIG. 2 shows the deduced translation (polypeptide)
product (SEQ ID NO:2). FIG. 6 shows a preliminary sequencing of
the genomic promoter region of mTERT (SEQ ID NO:4).
[0362] Cloning and Sequencing
of Genomic mTERT DNA
[0363] A lambda phage (called lambda-mTERT1) with an
approximately 23 kilobase pair (Kbp) insert containing the ATG
initiator for mTERT was cloned from a mouse genomic 129SV phage
library (Stratagene, San Diego, Calif.) using a mTERT cDNA probe
(residues 1586 to 1970 from SEQ ID NO:1). Two subfragments of
lambda-mTERT1 (an 8 Kbp HindIII and a 6 Kbp BglII fragment) were
found to hybridize to portions of pGRN227 in a Southern
hybridization experiment, see map, FIG. 7. The 8kb HindIII phage
DNA fragment was subcloned into the HindIII site of Bluescript
KS(+) (Stratagene, San Diego, Calif.) (called B2.18). The 6kb
BglII fragment, which begins just downstream of the ATG
initiator codon and extends in the 3' direction, was subcloned
into the BamHI site of Bluescript KS(+) (called
pmTERTgen-BglII). A preliminary DNA sequence of a portion of
B2.18 containing the ATG initiator and extending upstream is
shown in FIG. 8 (SEQ ID NO:5). Comparison of the genomic
sequence (FIG. 8) versus the mTERT cDNA sequence (FIG. 1)
indicates a probable 102 bp intron at position 2306 to 2407
(residues as numbered in FIG. 8). A 104 bp intron is in the
analogous position in hTERT.
[0364] Cloning and Sequencing
mTERT Species
[0365] The invention provides isolated, purified, and
recombinant genes for mTERT, including mTERT alleles,
homologues, and isoforms. The invention provides an example of
an mTERT nucleic acid and polypeptide species, SEQ ID NO:1 and
SEQ ID NO:2, respectively, and describes the structural features
common to mTERT species that can be to detect and identify mTERT
isoforms, alleles and homologs. The conservation of these intron
sites between mouse and human TERTs predicts that the first exon
constitutes a functional amino acid domain, the alteration or
loss of this domain could effect a change in TERT function. The
invention provides nucleic acid and protein reagents encoding or
comprising this domain which can be used to restore a TERT
function to TERT molecules missing this domain or to provide
that function in vitro or in vivo.
[0366] mTERT nucleic acid sequence (from cDNA of SEQ ID NO:1)
and protein sequence information (SEQ ID NO:2) can be used to
prepare PCR primers and oligonucleotides for the identification
of telomerase gene(s) and cDNA. PCR primers pairs that can
amplify sequences conserved amongst mTERT species are preferred
reagents of the invention and are useful to amplify directly new
mTERT isoforms, homologues and alleles. Alternatively, such
oligonucleotides are useful to detect mTERT-encoding nucleic
acid using a variety of hybridization techniques and conditions.
These oligonucleotides can be generated using any known
technique, including PCR, enzymatic restriction digestion of
isolated DNA or organic synthesis. These nucleic acids can be
labeled for detection and hybridized to DNA or RNA by any known
technique, as described above.
[0367] Total RNA can be extracted and enriched for mRNA using
the QuickPrep Micro mRNA Purification Kit (Pharmacia,
Piscataway, N.J.) according to the manufacturer's instructions.
The mRNA can then be used to make cDNA templates by reverse
transcription, using, e.g., the avian myeloblastosis virus (AMV)
reverse transcriptase (Pharmacia), as described by Sambrook. PCR
is performed on the cDNA using, for example, a Techne PHC-3
thermal cycler (Techne, Princeton, N.J.) with any set of primers
with sequence complementary or identical to or based on a known
mTERT, or other TERT, sequence. PCR can also be used to amplify
telomerase sequences from murine genomic DNA. Alternative
variations of traditional PCR can be used, such as RACE, as
described above. As noted above, PCR amplification can use a
variety of annealing conditions. For example, mTERT can be
amplified using the following cycling protocol: denaturing at
94[deg.] C., 45 seconds; annealing at 60[deg.] C., 45 seconds;
and extension at 72[deg.] C., 90 seconds. This can be repeated
for a total of about 30 to 40 cycles, yielding a DNA product,
which can be purified. The PCR product can be sequenced by any
known technique, such as the dideoxy-chain termination method
using a Dye Terminator Cycle Sequencing Kit(TM) Ready Reaction
Kit (Applied Biosystems, Foster City, Calif.) and a Model 373A
DNA Sequencer (Applied Biosystems). The PCR product, once
identified as an mTERT sequence, can be further labeled and used
as a hybridization probe, as described above.
[0368] Computer databases and programs can be used to analyze
the resultant DNA sequence for its sequence identity, or
homology, to known murine and other related TERT sequences, as
described above. For example, PC/Gene(TM) software
(IntelliGenetics Inc., Mountain View, Calif.) aligns sequences
and displays open reading frames. BLAST N and BLAST D search
algorithms can be employed to search the GenBank database (NIH,
Bethesda, Md.) for any matches between the derived mTERT
sequence and known mTERT and other TERT sequences.
Example 2
RNase Protection Assay for
Detection and Quantitation of TERT mRNA
[0369] RNase protection assays can be used to detect, monitor,
or diagnose the presence of an mTERT mRNA or a variant mRNA. An
RNase protection assay is a reliable, sensitive, and
quantifiable assay for detection of mTERT RNA. One illustrative
RNase protection probe is an in vitro synthesized RNA comprised
of sequences complementary to mTERT mRNA sequences and
additional, non-complementary sequences. The latter sequences
are included to distinguish the full-length probe containing
these sequences from a probe that has only complementary
sequences. In a positive assay, the complementary sequences of
the probe are protected from RNase digestion, because they are
hybridized to mTERT mRNA. The non-complementary sequences
(single-stranded sequences) are digested away from the probe by
the RNase.
[0370] The following illustrative example describes an RNase
protection assay which can be used to detect and quantify mTERT
mRNA. Also, see, e.g., Ma (1996) Methods 10:273-278 and Ausubel
(1987) supra, chapter 4.7, for general details on RNase
protection assay protocols; Kenrick (1997) Nucleic Acids Res.
25:2947-2948, describing a method to quantify mRNA levels using
RNase protection and scintillation proximity assay technologies,
a variety of mTERT protection probes can be designed for use
with mouse RNA. The probes can differ in their sequence
complementary to mTERT, but each may contain identical
non-complementary sequences, i.e., derived from the SV40 late
mRNA leader sequence. Probes designed for use in this exemplary
RNase protection assay can be chimerical antisense RNA probes.
They can comprise the initiator G from the T7 promoter, 32
nucleotides of the SV40 late leader (Chiou (1991) J. Virol.
65:6677-6685) and about 150 nucleotides to about 200 or more
nucleotides of antisense mTERT. Using T7 RNA polymerase and
radioactive guanosine, probes can be labeled to generate probes
that are 800,000 cpm/pmol.
[0371] To conduct the assay, either probe can be hybridized to
RNA, i.e., polyA+ RNA, from a test sample. T1 ribonuclease and
RNase a are then added. After RNase digestion, probe RNA is
purified and analyzed by gel electrophoresis.
[0372] RNAse protection probes can be generated by in vitro
transcription using T7 RNA polymerase. Radioactive or otherwise
labeled ribonucleotides can be included for synthesis of labeled
probes. The templates for the in vitro transcription reaction to
produce the RNA probes are PCR products. The illustrative probes
described above can be synthesized using T7 polymerase following
PCR amplification of mTERT DNA using primers that span the
corresponding complementary region of the mTERT gene or mRNA. In
addition, the downstream primer contains T7 RNA polymerase
promoter sequences and the non-complementary sequences.
[0373] RNase protection probes are hybridized to poly a+ RNA,
then digested with T1 Ribonuclease and RNase a, as described in
Ausubel. The plasmid containing the TERT insert is linearized
with restriction endonuclease. Transcription initiated with T7
RNA polymerase yields a runoff transcript. Transcripts are
quantified by the inclusion of <35> S UTP in the
nucleotide pool (400 cpm/pmol uridine). Protected probes of the
correct length are quantified by comparing them with known
quantities of an in vitro generated standard.
Example 3
Expression of mTERT in
Bacteria, Yeast, Insect and Mammalian Cells
[0374] The following example details the design of
mTERT-expressing bacterial expression vectors to produce large
quantities of full-length, biologically active mTERT (SEQ ID
NO:2). Generation of biologically active mTERT in this manner is
useful for telomerase enzyme reconstitution assays, assaying for
telomerase activity modulators, analysis of the activity of
newly isolated species of telomerase, identifying and isolating
compounds which specifically associate with telomerase, analysis
of the activity of telomerase which has been site-specifically
mutated, as described above, to analyze the secondary, tertiary
or quaternary structure of mTERT and telomerase enzyme, as by
crystallization and diffraction analysis or NMR, and as an
immunogen, for example.
[0375] pThioHis a/hTERT
Bacterial Expression Vector
[0376] To produce large quantities of full-length or
subfragments of mTERT (SEQ ID NO:2), the bacterial expression
vector pThioHis a (Invitrogen, San Diego, Calif.) can be used.
In one embodiment, the vector incorporates an mTERT-coding
insert including the full-length or partial sequence encoding
mTERT (SEQ ID NO:2). This expression vector is designed for
inducible expression in bacteria.
[0377] The vector can be also induced to express, in E. coli,
high levels of a fusion protein composed of a cleavable, HIS
tagged thioredoxin moiety and the full length or subfragment of
the mTERT protein.
[0378] pGEX-2TK wth mTERT, with
HIS-8 Tag
[0379] To produce large quantities of a full length of a
fragment of mTERT, another E. coli expression vector pGEX-2TK
(Pharmacia Biotech, Piscataway N.J.) construct can be used. This
construct can contain a subsequence or all of the mTERT coding
sequence (SEQ ID NO:1) and a sequence encoding eight consecutive
histidine residues (HIS-8 Tag).
[0380] Vectors with mTERT cDNA
Lacking 5'-non-coding Sequence
[0381] As described above, in one embodiment, the invention
provides for an mTERT that is modified in such a site-specific
manner to facilitate cloning into bacterial, mammalian, yeast
and insect expression vectors without any 5' untranslated mTERT
sequence. In some circumstances, minimizing the amount of
non-protein encoding sequence allows for improved protein
production (yield) and increases mRNA stability. In this
embodiment of the invention, the 5' non-coding region is removed
before cloning into the bacterial expression vector.
[0382] This is effected by engineering an additional restriction
endonuclease site just upstream (5') to the start (ATG) codon of
mTERT cDNA. The creation of a restriction site just 5' to the
coding region of the protein allows for design and production of
fusion proteins, including labels and peptide TAGs, for
immunodetection and purification.
[0383] Plasmids with mTERT cDNA
Lacking 3'-non-coding Sequence
[0384] As discussed above, the invention provides expression
vectors containing TERT-encoding nucleic acids in which some or
all non-coding sequences have been deleted. In some
circumstances, minimizing the amount of non-protein encoding
sequence allows for improved protein production (yield) and
increased mRNA stability. In this embodiment, the 3'
untranslated region of mTERT is deleted before cloning into the
bacterial expression plasmid.
[0385] MPSV-mTERT Expression
Plasmids
[0386] The invention also provides for a method of expressing
mTERT in mammalian cells that can give the highest possible
expression of recombinant mTERT without actually modifying the
coding sequence (e.g. optimizing codon usage). In one
embodiment, the invention provides MPSV mammalian expression
plasmids (described by Lin J-H (1994) Gene 47:287-292) capable
of expressing the mTERTs of the invention. The MPSV plasmids can
be expressed either as stable or transient clones.
[0387] In this expression method, while the mTERT coding
sequence (SEQ ID NO:1) itself is unchanged, exogenous
transcriptional control elements are incorporated into the
vector. The myeloproliferative sarcoma virus (MPSV) LTR
(MPSV-LTR) promoter, enhanced by the cytomegalovirus (CMV)
enhancer, is incorporated for transcriptional initiation. This
promoter consistently shows higher expression levels in cell
lines (see Lin J-H (1994) supra), a Kozak consensus sequence can
be incorporated for translation initiation (see Kozak (1996)
Mamm. Genome 7:563-574. All extraneous 5' and 3' untranslated
mTERT sequences can be removed to insure that these sequences do
not interfere with expression, as discussed above.
[0388] The invention also provides for an mTERT "antisense"
sequence containing plasmid. This vector is identical to that
described above except that the mTERT insert is the antisense
sequence of mTERT SEQ ID NO:1.
[0389] Two selection markers, PAC
(Puromycin-N-acetyl-transferase=Puromycin resistance) and HyB
(Hygromycin B=Hygromycin resistance) are present for selection
of the plasmids after transfection (see discussion referring to
selectable markers, above). Double selection using markers on
both sides of the vector polylinker can ensure the stable
maintenance of the mTERT coding sequence, a DHFR (dihydrofolate
reductase) encoding sequence can be included to allow
amplification of the expression cassette after stable clones are
made. Other means of gene amplification can also be used to
increase recombinant protein yields.
[0390] The invention also provides MPSV mammalian expression
plasmids containing mTERT fusion proteins. In one embodiment,
the mTERT sequence, while retaining its 5' untranslated region,
is linked to an epitope flag, such as the IBI FLAG
(International Biotechnologies Inc. (IBI), Kodak, New Haven,
Conn.) and inserted into the MPSV expression plasmid. This
particular construct contains a Kozak translation initiation
site. The expressed fusion protein can be purified using the M-1
anti-FLAG octapeptide monoclonal antibody (IBI, Kodak, supra).
[0391] Bacterial Expression
Vectors Using Antibiotic Selection Markers
[0392] The invention also provides bacterial expression vectors
that can contain selection markers to confer a selectable
phenotype on transformed cells and sequences coding for episomal
maintenance and replication such that integration into the host
genome is not required. For example, the marker may encode
antibiotic resistance, particularly resistance to
chloramphenicol (see Harrod (1997) Nucleic Acids Res. 25:
1720-1726), kanamycin, G418, bleomycin and hygromycin, to permit
selection of those cells transformed with the desired DNA
sequences, see for example, Blondelet-Rouault (1997) supra;
Mahan (1995) Proc. Natl. Acad. Sci. USA 92:669-673. In one
embodiment, the full length mTERT (SEQ ID NO:1) is cloned into a
modified Bluescript plasmid vector. The mTERT ORF is oriented in
the opposite orientation of the Lac promoter. This makes a
plasmid that is suitable for mutagenesis of plasmid inserts,
such as mTERT nucleic acids of the invention. mTERT can be
site-specifically altered, e.g., in motif regions, to create,
e.g., dominant negative mTERT mutants, as described above. This
plasmid can also be used for in vitro transcription of mTERT
using the T7 promoter and in vitro transcription of antisense
mTERT using the T3 promoter.
Expression of mTERT Telomerase
in Yeast
[0393] The invention provides mTERT-expressing yeast expression
vectors to produce large quantities of full-length, biologically
active mTERT, or fragments thereof including the mTERT
polypeptide comprising a sequence as set forth in SEQ ID NO:2.
[0394] Pichia pastoris
Expression Vector
[0395] To produce large quantities of full-length, biologically
active mTERT (SEQ ID NO:2), or a fragment thereof, the Picha
pastoris expression vector pPICZ B (Invitrogen, San Diego,
Calif.) can be used. The mTERT-coding insert is derived from SEQ
ID NO:1. This nucleotide sequence encodes a polypeptide
comprising the full-length sequence of mTERT as set forth in SEQ
ID NO:2. This expression vector is designed for inducible
expression in P. pastoris of high levels of full-length,
unmodified mTERT protein, or a fragment thereof (SEQ ID NO:2).
Expression is driven by a yeast promoter, but the expressed
sequence utilizes the mTERT initiation and termination codons.
The pPICZ B/hTERT vector (Invitrogen, San Diego, Calif.) is used
to transform the yeast.
Expression of mTERT in Insect
Cells
[0396] The following example details the design of
TERT-expressing insect cell expression vectors to produce large
quantities of full-length, biologically active TERT, such as
mTERT (SEQ ID NO:2), or subfragments thereof.
[0397] Baculovirus Expression
Vector pBlueBacHis2 B
[0398] mTERT coding sequence can be cloned into the baculovirus
expression vector pVL1393 (Invitrogen, San Diego, Calif.). This
construct is subsequently cotransfected into Spodoptera
fungupeida (sf-9) cells with linearized DNA from Autograph
California nuclear polyhidrosis virus (Baculogold-AcMNPV). The
recombinant baculoviruses obtained are subsequently plaque
purified and expanded following published protocols, as
discussed above. This expression vector is designed for
expression in insect cells of high levels of full-length mTERT
protein, or subfragments thereof. Expression is driven by a
baculoviral polyhedrin gene promoter, but the expressed sequence
utilizes the mTERT initiation and termination codons.
[0399] To produce large quantities of full-length, biologically
active mTERT (SEQ ID NO:2), or subfragments thereof, the
baculovirus expression vector pBlueBacHis2 B (Invitrogen, San
Diego, Calif.) can be used. The mTERT-coding insert can comprise
nucleotides as set forth in SEQ ID NO:1. This nucleotide
sequence includes the full-length sequence encoding mTERT (SEQ
ID NO:2).
[0400] Another embodiment provides for a full length mTERT with
6HIS and Anti-Xpress tags. This vector also contains an insert
consisting of all or a subsequence of SEQ ID NO:1. The vector
directs expression in insect cells of high levels of full length
mTERT, or fragments thereof, fused to cleavable 6-histidine and
an Anti-Xpress tags with an enterokinase cleavage site.
[0401] Baculovirus Expression
Vector pBlueBac4.5
[0402] To further produce large quantities of full-length,
biologically active mTERT (SEQ ID NO:2), or subfragments
thereof, a second baculovirus expression vector, pBlueBac4.5
(Invitrogen, San Diego, Calif.) can be used. The mTERT-coding
insert can also consist of nucleotides comprising all or a
subsequence of SEQ ID NO:1.
[0403] Baculovirus Expression
Vector pMelBacB
[0404] To further produce large quantities of full-length,
biologically active mTERT (SEQ ID NO:2), or sub fragments
thereof, a third baculovirus expression vector, pMelBacB
(Invitrogen, San Diego, Calif.) can be selected. The
mTERT-coding insert can also consist of nucleotides comprising
all or a subsequence of SEQ ID NO:1.
[0405] pMelBacB can direct expression of full length mTERT, or
subfragments thereof (SEQ ID NO:2), in insect cells to the
extracellular medium through the secretory pathway using the
melittin signal sequence. High levels full length mTERT (SEQ ID
NO:2) are thus secreted. The melittin signal sequence is cleaved
upon excretion, but is part of the protein pool that remains
intracellular.
Expression of mTERT in
Mammalian Cells
[0406] The recombinant mTERT of the invention can be produced in
large quantities as full-length, biologically active mTERT, or
subfragments thereof (SEQ ID NO:2), in a variety of mammalian
cell lines.
[0407] mTERT Expressed in 293
Cells using Episomal Vector pEBVHis
[0408] In one embodiment, an episomal vector, pEBVHis
(Invitrogen, San Diego, Calif.) engineered to express an mTERT
(SEQ ID NO:2) fusion protein comprising mTERT fused to an
N-terminal extension epitope tag, the Xpress epitope
(Invitrogen, San Diego, Calif.). The mTERT open reading frame
(ORF) is cloned so that the mTERT ORF, or subfragments thereof,
are in the same orientation as the Rous Sarcoma virus (RSV)
promoter. In this orientation, the His6 flag is relatively
closer to the N-terminus of mTERT, a control vector can also be
constructed to contain as an insert the antisense sequence of
the fusion protein (mTERT and the epitope tag), for
co-transfection, to be used as a negative control.
[0409] The vectors are transfected into mammalian cells, and
translated mTERT is identified and isolated using an antibody
specific for the Xpress epitope. pEBVHis is a hygromycin
resistant EBV episomal vector that expresses the protein of
interest fused to an N-terminal peptide. Cells carrying the
vector are selected and expanded, then nuclear and cytoplasmic
extracts prepared. These and control extracts are
immunoprecipitated with anti-Xpress antibody, and the
immunoprecipitated beads are tested for mTERT and/or telomerase
enzyme expression and activity by the various assays described
above.
Expression of Recombinant mTERT
in Mortal, Normal Diploid Human or Mouse Cells
[0410] In one embodiment of the invention, recombinant mTERT and
necessary telomerase enzyme complex components can be expressed
in normal, diploid mortal cells to create an indefinitely
proliferating cell line, to directly immortalize the cells, or
to facilitate immortalizing them. This allows one to obtain
diploid immortal cells with an otherwise normal phenotype and
karyotype.
[0411] Sense mTERT (SEQ ID NO:1) and antisense mTERT
(complementary to SEQ ID NO:1) are cloned into a CMV vector.
These vectors are purified and transiently transfected into two
normal, mortal, diploid mammalian cell clones. Analysis of
telomerase enzyme activity can be done using a TRAP assay, as
described above, e.g., utilizing the TRAPezc Kit (Oncor, Inc.,
Gaithersburg, Md.). Transfection of sense mTERT-but not
antisense mTERT-generates telomerase enzyme activity.
[0412] Vectors for Regulated
Expression of mTERT in Mammalian Cells: Inducible and
Repressible Expression of mTERT
[0413] The invention provides vectors which can be manipulated
to induce or repress the expression of the mTERT of the
invention. For example, mTERT (SEQ ID NO:1) is cloned into the
Ecdysone-Inducible Expression System from Invitrogen (San Diego,
Calif.) and the Tet-On and Tet-off tetracycline regulated
systems from Clontech Laboratories, Inc. (Palo Alto, Calif.).
Such inducible expression systems are provided for use in the
methods of the invention where it is important to control the
level or rate of transcription of transfected mTERT. For
example, the invention provides cell lines made indefinitely
proliferating or immortalized through the expression of mTERT;
such cells can be rendered "mortal" by inhibition of mTERT
expression by the vector through its transcriptional controls,
such as the Tet-Off system. The invention also provides methods
of expressing mTERT only transiently to avoid the constitutive
expression of mTERT, which may lead to unwanted
"immortalization" of transfected cells, as discussed above.
[0414] The Ecdysone-Inducible Mammalian Expression System is
designed to allow regulated expression of the gene of interest,
such as mTERT, in mammalian cells. The system is distinguished
by its tight regulation that allows almost no detectable basal
expression and greater than 200-fold inducibility in mammalian
cells. The expression system is based on the heterodimeric
ecdysone receptor of Drosophila. The Ecdysone-Inducible
Expression System uses a steroid hormone ecdysone analog,
muristerone a, to activate expression of mTERT via a
heterodimeric nuclear receptor. Expression levels have been
reported to exceed 200-fold over basal levels with no effect on
mammalian cell physiology (No (1996) "Ecdysone-Inducible Gene
Expression in Mammalian Cells and Transgenic Mice" Proc. Natl.
Acad. Sci. USA 93, 3346-3351). Once the receptor binds ecdysone
or muristerone, an analog of ecdysone, the receptor activates an
ecdysone-responsive promoter to give controlled expression of
the gene of interest, as mTERT. In the Ecdysone-Inducible
Mammalian Expression System, both monomers of the heterodimeric
receptor are constitutively expressed from the same vector,
pVgRXR. The ecdysone-responsive promoter, which ultimately
drives expression of the gene of interest, is located on a
second vector, pIND, which drives the transcription of the gene
of interest. In one embodiment, mTERT is cloned in the pIND
vector (Clontech Laboratories, Inc, Palo Alto, Calif.)
containing five modified ecdysone response elements (E/GREs)
upstream of a minimal heat shock promoter and the multiple
cloning site. The construct is then transfected in cell lines
which have been pre-engineered to stably express the ecdysone
receptor. After transfection, cells are treated with muristerone
a to induce intracellular expression of the gene of interest
from pIND.
[0415] The Tet-on and Tet-off expression systems (Clontech, Palo
Alto, Calif.) give access to the regulated, high-level gene
expression systems described by Gossen (1992) "Tight control of
gene expression in mammalian cells by tetracycline responsive
promoters" Proc. Natl. Acad. Sci. USA 89:5547-5551, for the
Tet-Off transcription repression system; and Gossen (1995)
"Transcriptional activation by tetracycline in mammalian cells"
Science 268:1766-1769, for the Tet-On inducible transcriptional
system. In "Tet-Off" transformed cell lines, gene expression is
turned on when tetracycline (Tc) or doxycycline ("Dox;" a Tc
derivative) is removed from the culture medium. In contrast,
expression is turned on in Tet-On cell lines by the addition of
Tc or Dox to the medium. Both methods permit expression of
cloned genes to be regulated closely in response to varying
concentrations of Tc or Dox. This method uses the "pTRE" as a
response plasmid that can be used to express a gene of interest,
such as mTERT. pTRE contains a multiple cloning site (MCS)
immediately downstream of the Tet-responsive PhCMV*-1 promoter.
cDNAs or genes of interest inserted into one of the sites in the
MCS will be responsive to the tTA and rtTA regulatory proteins
in the Tet-Off and Tet-On systems, respectively. PhCMV*-1
contains the Tet-responsive element (TRE), which consists of
seven copies of the 42-bp tet operator sequence (tetO). The TRE
element is just upstream of the minimal CMV promoter (PminCMV),
which lacks the enhancer that is part of the complete CMV
promoter in the pTet plasmids. Consequently, PhCMV*-1 is silent
in the absence of binding of regulatory proteins to the tetO
sequences. The cloned insert must have an initiation codon. In
some cases, addition of a Kozak consensus ribosome binding site
may improve expression levels; however, many cDNAs have been
efficiently expressed in Tet systems without the addition of a
Kozak sequence. pTRE-Gene X plasmids are cotransfected with
pTK-Hyg to permit selection of stable transfectants.
[0416] Setting up a Tet-Off or Tet-On expression system
generally requires two consecutive stable transfections to
create a "double-stable" cell line that contains integrated
copies of genes encoding the appropriate regulatory protein and
TERT under the control of a tet-responsive element (TRE). In the
first transfection, the appropriate regulatory protein is
introduced into the cell line of choice by transfection of a
"regulator plasmid" such as pTet-Off or pTet-On vector, which
express the appropriate regulatory proteins. mTERT cloned in the
pTRE "response plasmid" is then introduced in the second
transfection to create the double-stable Tet-Off or Tet-On cell
line. Both methods give very tight on/off control of gene
expression, regulated dose-dependent induction, and high
absolute levels of gene expression.
Expression of Recombinant mTERT
with DHFR and Adenovirus Sequences
[0417] In one embodiment, a plasmid construct is prepared for
transient expression of mTERT cDNA in mammalian cells, a Kozak
consensus is inserted at the 5' end of mTERT coding sequence.
The mTERT insert can be designed to contain no 3' or 5' UTR. The
mTERT cDNA is inserted into the EcoRI site of p91023(B) (Wong
(1985) Science 228:810-815). The mTERT insert is in the same
orientation as the DHFR ORF. The expression vector is useful for
transient expression.
[0418] The selected plasmid contains an SV40 origin and enhancer
just upstream of an adenovirus promoter, a tetracycline
resistance gene, an E. coli origin and an adenovirus VAI and
VAII gene region. This expression cassette contains, in the
following order: the adenovirus major late promoter, the
adenovirus tripartite leader, a hybrid intron consisting of a 5'
splice site from the first exon of the tripartite leader and a
3' splice site from the mouse immunoglobulin gene; the mTERT
cDNA; the mouse DHFR coding sequence; and the SV40
polyadenylation signal.
[0419] The adenovirus tripartite leader and the VA RNAs have
been reported to increase the efficiency with which
polycistronic mRNAs are translated. DHFR sequences have been
reported to enhance the stability of hybrid mRNA. DHFR sequences
also can provide a marker for selection and amplification of
vector sequences. See Logan (1984) Proc. Natl. Acad. Sci. USA
81:3655); Kaufman (1985) Proc. Natl. Acad. Sci. USA 82: 689; and
Kaufman (1988) Focus (Life Technologies, Inc.) Vol. 10, no. 3).
Example 4
mTERT Transgenic Mice and mTERT
"Knock Out" Mice
[0420] The invention provides transgenic cells and animals which
can express an introduced recombinant mTERT. The recombinant
mTERT can be wild-type (native) or modified. An exogenous mTERT
endogenous mTERT can remain function. The methods of the
invention include screening for mTERT modulators in animals by
reconstituting an mTERT and/or murine telomerase enzyme in an
animal, e.g., a transgenic animal.
[0421] The in vivo assays methods include "knockout" models, in
which one or several units of the endogenous telomerase,
telomerase RNA moiety and/or telomerase-associated proteins have
first been deleted or inhibited before an exogenous murine
telomerase activity (full or partial) is reconstituted. The
transgenic animals of the invention also provide methods of
expressing the mTERT and murine telomerase compositions of the
invention and providing indefinitely proliferating and
immortalized, otherwise normal cells which can be used to
express compositions of interest.
[0422] The mTERT gene can be "knocked out" using conventional
techniques, usually involving homologous recombination, as
discussed above. Thus, the invention provides for a unique
targeting vector comprising the mTERT nucleic acid sequences of
the invention, including at least part of SEQ ID NO:1, for use
in homologous recombination to create a mouse that cannot
express its endogenous mTERT. The targeting vector is usually
inserted in a pluripotential embryonic cell or cell line, such
as mouse embryonic stem (ES) cells, to disrupt the complementary
endogenous gene by homologous recombination. Animals with the
targeted and disrupted gene of interest, lacking or having
impaired ability to express that gene, are bred.
[0423] Means of constructing such vectors, inserting them into
the cells of interest, breeding animals, and the like, to
construct these "knock-out" animals are described herein, and
generally well described in the scientific and patent
literature, see also, e.g., U.S. Ser. No. 08/623,166, filed 28
Mar. 1996, describing construction of hTERC (hTR) knockout mice.
See also, e.g., for further illustrative examples of
construction of "knockout mice," Ma (1997) J. Clin. Invest.
100:957-962; Schwindinger (1997) Endocrinology 138:4058-4063;
Stenbit (1997) Nat. Med. 3:1096-1101; Moreadith (1997) J. Mol.
Med. 75:208-216; Udy (1997) Exp. Cell Res. 231:296301,
describing use of isogenic lines to support homologous
recombination events; Taghian (1997) Mol. Cell. Biol.
17:638&6393, on use of chromosomal double-strand breaks to
induce gene conversion, chromosomal and extrachromosomal
recombination, and gene targeting at high frequency in mammalian
cells; Templeton (1997) Gene Ther. 4:700-709, for methods to
improve the efficiency of gene correction in mouse embryonic
stem cells using homologous recombination; Araki (1997) Nucleic
Acids Res. 25:868-872; describing targeted, site-directed
integration of DNA using mutant lox sites in embryonic stem
cells; and, Kühn (1997) Curr. Opin. Immunol. 9:183-188,
describing methods for site-specific and homologous DNA
recombination expanding the potential of gene targeting in
embryonic stem cells.
[0424] Plasmid Construction and
Production of Transgenic Mice
[0425] The construction and use of transgenic mice that express
introduced mTERT, hTERT, or TERT genes is described below.
[0426] EcoRI cDNA fragments containing the full length ORF for
mTERT (from pGRN188), hTERT (from pGRN121), and hTERT-D868A
(from pGRN202) were ligated into the pCAGGS expression vector
containing the chicken beta-actin promoter, cytomegalovirus
enhancer element, beta-actin intron and bovine globin
poly-adenylation signal (Niwa (1991) Gene 108:193-199). The
entirety of each insert with promoter, coding, and
polyadenylation sequences were liberated with HinDIII and SalI
restriction digests, gel purified, and then injected into C57
BL/6*FVB fertilized eggs (general procedure described in
Morgenbesser (1995) EMBO J. 14:743-746). The DNA injected eggs
were then transplanted to pseudopregnant female mice resulting
in 26 newborns. Incorporation of the transgene was identified by
Southern and slot blot analysis using mTERT cDNA fragment
probes. Three transgene positive founder lines were identified.
[0427] Construction of mTERT
Gene Knockout Mice
[0428] The construction of a transgenic mouse line homozygous
for an mTERT deletion is described below, this mouse line is
also called a "knockout" mouse line in that it is missing
functional copies of both mTERT alleles (the invention also
provides for mice in which mTERT expression is modified, or in
which only one allele of mTERT is deleted or modified, as
discussed above). The mTERT -/- mouse knockout line can be used
to assess mTERT, hTERT, telomerase, and telomere maintenance and
function in vivo or ex vivo. Mutated or deleted forms of TERT
genes can be also introduced into the mTERT -/- cells or mice to
create new transgenic mice or cells that can assess the
functional consequences of the alterations. In this manner
functional domains of TERT can be identified and their functions
assigned. The restoration or loss of functions associated with
TERT alterations could identify TERT- or telomerase-interacting
proteins.
[0429] In another embodiment, the mTERT -/- mice are used to
assess in vivo or ex vivo effects of telomerase inhibitory
compounds on animals, tissues and cells in the absence of
telomerase enzyme activity. This is a useful biological model
method to assess the pharmacokinetics and potential for adverse
side effects of telomerase enzyme modulators (e.g., mTERT
inhibitory compounds). Transgenic knockout mTERT -/- lines with
introduced mutant TERTs could be used to assess the in vivo or
ex vivo mode of action of telomerase enzyme modulating compounds
and to improve their agonist, inhibitory or interaction
properties.
[0430] The invention also provides cells and mouse lines in
which a recombinant TERT gene with alterations to a
transcriptional regulatory region (e.g., the promoter or other
region) in place of a TERT genomic sequence (e.g., optionally
mTERT or hTERT) is reintroduced into the mTERT -/- mice to
assess cis-acting (e.g., promoter) or other regulatory regions.
These mouse lines can also be used to assess the biological
consequences of regulatory region alterations or the
inappropriate expression of the introduced TERT under the
control of the modified regulatory region. These methods can
also be used to assess, alter, or improve the in vivo or ex vivo
actions of TERT affecting trans-activating transcriptional
regulatory agents. Such a method can modulate the expression of
the TERT promoter in order to, e.g., assert a therapeutic
effect.
[0431] The mouse mTERT 5' genomic region described above was
isolated by screening a 129/Sv mouse genomic library
(Stratagene, San Diego, Calif.) with a fragment spanning
nucleotides 1585-1970 of the mTERT cDNA (SEQ ID NO:1). The
targeting construct, pmTERTKO, utilized the mutant
neomycin-resistance and HSV thymidine kinase genes under the
control of the PKG promoter, and was constructed as generally
described in Serrano (1996) Cell 85:27-37. FIG. 9 presents a
schematic illustration of the targeting construct (vector)
pmTERTKO.
[0432] To construct the targeting construct (vector) an
approximately 2.8 Kbp EcoRI to XbaI fragment of B2.18 (discussed
above), designated Arm1, was ligated into pPNT (described by
Serrano (1996) supra) downstream of the Neo gene and upstream of
the thymidine kinase gene (FIG. 9). The 6 Kbp BglII fragment,
designated Arm2 (FIG. 9), was excised from pmTERTgen-BglII with
NotI and XhoI and ligated into these sites in pPNT upstream of
the Neo gene.
[0433] The pmTERTKO vector was linearized by NotI prior to being
electroporated into WW6 ES cells (Ioffe (1995) Proc. Natl. Acad.
Sci. USA 144:500-510). Homologous recombination of the targeting
construct pmTERTKO into the mTERT gene results in replacement of
approximately 600 base pairs (bp) of the mTERT genomic sequence
encompassing the ORF initiating methionine by the construct's
neomycin resistance gene.
[0434] Upon transfection into the mouse ES cells and homologous
recombination of the construct, the initiator methionine of
mTERT was replaced by a portion of the pmTERTKO vector sequence,
resulting in a "null" or "knocked-out" allele construct. Clones
in which homologous recombination has occurred are selected for
with G418 (150 mg/ml active component) and 2 mM gancyclovir.
mTERT heterozygous ES clones were identified by Southern blot
analysis for the presence of integrated pmTERTKO vector sequence
(the null allele). Positive clones were subsequently injected
into C57BL/6 blastocysts. Resultant male chimeras with greater
than 50% ES contribution, as judged by coat color, were mated
with C57BL/6 females. Germline transmission to agouti offspring
was confirmed by both Southern blot and PCR analysis of tail DNA
for the presence of the integrated vector sequence (the null
allele).
[0435] The utility of a mTERT knockout mouse line results from
the loss or modification of telomerase activity associated with
the gene deletions or modifications. Homozygous deletion
knockout mice and progeny will have no telomerase activity since
no functional mTERT protein will be produced. The telomeres of
these homozygous mTERT-mice will progressively shorten, placing
an upper limit on the replicative lifespan of its cells,
dependent on their telomere length and telomere shortening rate.
As observed with the mTERC (mTR) knockout mice (Blasco (1997)
Cell 91:25-34) the first generation mice will be fertile.
Subsequent generations will have shorter and shorter telomeres.
Eventually the progressive shortening will result in functional
impairment of chromosomes, leading to infertility. Impairment of
tissues with high proliferative capacity to replace their cells
through cell division is also seen. The rate of telomere
shortening in mTERC -/- mice (lacking telomerase enzyme
activity) resulted in fertility and cell replacement problems in
4 to 6 generations. mTERT -/- mice, also lacking telomerase
enzyme activity, will also have similar defects. The mTERT -/-
mice are distinguishable from mTERC -/- mice in that mTERC -/-
mice retain the ability to express a potentially active mTERT
protein which can interact with telomere proteins, chromosomal
structures, other nucleic acid moieties, regulatory proteins,
and the like. Thus, even in the absence of mTERC, mTERT can
modulate telomere structure and function outside of its telomere
addition function. Loss of these functions in the mTERT -/- mice
could, in some circumstances, lead to more rapid telomere loss,
altered telomere or chromosome function, altered cell cycle
regulation, and the like. This could lead to the inviability of
the first generation of mTERT -/- mice, a more rapid occurrence
of the phenotypes observed in the mTR -/- mice, or new
phenotypes.
[0436] In one embodiment, the mTERT -/- mice are mated with the
mTR -/- mice to create a double knockout line missing both mTERT
protein and the mouse telomerase RNA, mTERC. This is a mouse
line or cell line with a "clean" background useful for the
simultaneous assessment of TERT and telomerase RNA functions.
Altered mTERTs, hTERTs, mTERCs, and hTERCs are introduced to
assess the functional in vivo and ex vivo affects of the
alterations. These lines are particularly useful for assessing
the structure and function of hTERT and hTERC since a similar in
vivo or ex vivo model method in humans or human cells is
technically difficult or ethically impossible. Regions of TERT
and TERC interactions can be identified and assigned functions.
These lines also provide means to determine how telomerase or
TERT modulators affect hTERT and hTERC in vivo. The method is
used to improve the telomerase modulatory (e.g., inhibitory)
properties of compounds affecting human telomerase. The method
can also be used to assess, and reduce, unwanted or secondary
(side) effects of modulatory compounds in the context of a whole
animal.
Example 5
Antibodies Directed to mTERT
and Mouse Telomerase
[0437] The antibodies of the invention can be used in several
embodiments of the invention as described above, including,
e.g.: the isolation of mTERT, murine telomerase enzyme,
telomerase-associated proteins; inhibition of telomerase
activity by binding to telomerase; identifying the location of
telomerase in situ.
[0438] mTERT protein fragments to be used as immunogens are
generated using expression vectors, typically bacterial
expression vectors. Specifically, in one embodiment, an E. coli
expression vector pGEX-2TK (Pharmacia Biotech, Piscataway N.J.)
construct is used containing various subfragments of
mTERT-encoding nucleic acid sequences (cDNA, SEQ ID NO:1). The
isolated or purified fusion proteins are used in conventional
protocols, as described above, to generate rabbit polyclonal
antisera and mouse polyclonal antisera and monoclonal
antibodies, or to screen phage display libraries, as discussed
above.
Example 6
mTERT Telomerase Promoter
Expression Constructs
[0439] The present invention also provides methods and reagents
relating to cis-acting transcriptional and translational mTERT
regulatory elements. Examples of cis-acting transcriptional
regulatory elements include promoters and enhancers of the mTERT
gene. The identification and isolation of cis- and trans-acting
regulatory agents provide further methods and reagents for
identifying additional agents that modulate transcription and
translation of mTERT.
[0440] The present invention also provides recombinant vectors
in which an mTERT promoter is operably linked to a reporter
gene. Such constructs are useful, inter alia, in screens to find
agents that modulate the activity of the promoter of the TERT
gene. In one illustrative embodiment, the reporter gene is
alkaline phosphatase and is derived from the well known pSEAP2
reporter gene system (marketed by Clontech, Palo Alto, Calif.).
In one embodiment, to assess the ability of the mTERT promoter
to drive transcription, the mTERT promoter is fused to the
coding sequence of the human secreted alkaline phosphatase
(SEAP).
[0441] SEAP is a secreted form of human placental alkaline
phosphatase (Berger (1988) "Secreted placental alkaline
phosphatase: a powerful new quantitative indicator of gene
expression in eukaryotic cells" Gene 66: 1-10; Bronstein (1996)
Clin. Chem. 42:1542-1546). This fusion protein-expressing
construct can be inserted into any mammalian expression vector
for transient transfection into cells. The SEAP reporter gene
encodes a truncated form of the placental enzyme which lacks the
membrane anchoring domain, thereby allowing the protein to be
secreted efficiently from transfected cells. Levels of SEAP
activity detected in the culture medium have been shown to be
directly proportional to changes in intracellular concentrations
of SEAP mRNA and protein (Berger (1988) Gene, supra; Cullen
(1992) "Secreted placental alkaline phosphatase as a eukaryotic
reporter gene" Methods Enzymol. 216:362-368). Thus, there is a
direct correlation between levels of SEAP secreted and the
activity of the mTERT promoter using such constructs of the
invention.
[0442] Other embodiments include additional mTERT
promoter/reporter protein constructs to evaluate mTERT promoter
activity in different cells under varying conditions. Such
reporter proteins include, e.g., firefly luciferase,
beta-glucuronidase, beta-galactosidase, cloramphenicol
acetyl-transferase, and GFP.
Example 7
In Vitro Reconstitution of
Telomerase Activity with mTERT
[0443] To demonstrate that mTERT cDNA (SEQ ID NO:1) encodes
mTERT catalytic activity, in vitro telomerase enzyme
reconstitution assays can be performed, as described, e.g., by
Weinrich (1997) supra. mTERT was expressed alone or in
combination with hTERC, i.e., the mTERT-containing telomerase
enzyme was reconstituted using hTERC as the RNA moiety.
Resultant telomerase activity was measured by a modified version
of the TRAP assay, as described by Kim (1994) supra. As a
positive control, parallel assays were performed with hTERT and
hTERC. An RNase sensitive 6 bp ladder was generated by mTERT in
the presence of hTERC, but not in its absence, indicating that
the recombinant mTERT was transcribed and translated, and
telomerase enzyme activity was reconstituted, and an RNA moiety
was necessary for reconstitution of telomerase enzymatic
activity.
[0444] TRAP activity was not seen with the mTERT mutant,
mTERTDT, which lacks the telomerase specific T motif. These in
vitro reconstitution studies demonstrate that the mTERT cDNA
encodes telomerase RNA-dependent catalytic activity and, similar
to the human enzyme, the presence of the T motif is essential
for enzymatic catalysis.
[0445] These studies also demonstrate that mTERT and hTERC can
form a functional ribonucleoprotein complex despite species
differences in the telomerase enzyme RNA moieties, including a
longer template for hTERC (see Feng (1995) Science 269:1236-41;
Blasco (1995) Science 269:1267-70). This result suggests that,
within the context of this in vitro assay, these primary
nucleotide sequence differences in these telomerase RNA moieties
do not impact on higher order RNA structure and mTERT
protein-RNA interactions.
[0446] This example describes three mutants of mTERT which are
predicted to be deficient in a telomerase activity. These
mutations change amino acids in the conserved RT motifs
previously shown to be essential for RT function (Lingner (1997)
supra). The mutations are created using the procedures described
in Weinrich (1997) supra.
[0447] Four point mutants are generated in mTERT using pGRN190
as the mutagenesis vector. Plasmid pGRN190 is a mammalian
expression vector comprising the entire cDNA insert from
pGRN188, such that mTERT mRNA is transcribed from the MPSV
(myeloproliferative sarcoma virus) promoter. The construction of
pGRN190 was similar to that used to construct plasmid pGRN145,
described by Bodner, et al., Science, January 1998, vol.
279:349-352.
[0448] Mutants (1) to (3) are predicted to be deficient in a
telomerase enzyme activity. Oligonucleotide (oligo) sequences
for generating these point mutants are listed below with the
position (based on SEQ ID NO:1 residue numbering) and
restriction enzyme sites generated indicated in standard form:
[0449] (1) mF550A (5'-ACAGCTGCTTAGATCTTTCGCTTACATCACAGA-3') (SEQ
ID NO:17). This oligo generates a point mutation that changes
the second phenylalanine in motif T to an alanine (analogous to
the F651A in hTERT). This mutation is predicted to greatly or
completely reduce a telomerase activity. A BglII restriction
site is also introduced.
[0450] (2) mD701A (5'-TTGTTAAGGCAGCTGTGACCGGTGCCTATGATGCC-3')
(SEQ ID NO:18). This oligo generates a point mutation that
changes the aspartate to an alanine in motif A (analogous to the
D712A in hTERT). This mutation is predicted to greatly or
completely reduce a telomerase activity. PvuII and AgeI
restriction sites are also introduced.
[0451] (3) mD860A (5'-TACGTTTTGTTGCTGACTTTCTACTAGTGACGCCTCAC-3')
(SEQ ID NO:19). This oligo generates a point mutation that
changes the aspartate to an alanine in motif C (analogous to the
D868A in hTERT). This mutation is predicted to greatly or
completely reduce a telomerase activity. A SpeI restriction site
is also introduced.
[0452] (4) mD600A (5'-GGCATCACCAGGCCACGTGGCTGGCCATGCCCATC-3')
(SEQ ID NO:20). This oligo generates a point mutation that
changes an aspartate to an alanine upstream of motif 1. This
aspartate residue is not conserved between mTERT and hTERT
making a good control base change. No or little phenotypic
result is expected. A PmlI restriction site is also introduced
and a NheI restriction site is deleted.
[0453] It is understood that the examples and embodiments
described herein are for illustrative purposes only and that
various modifications or changes in light thereof will be
suggested to persons skilled in the art and are to be included
within the spirit and purview of this application and scope of
the appended claims. All publications, patents, patent
applications, and GenBank sequences cited herein are hereby
incorporated by reference for all purposes.
# SEQUENCE LIS
#TING
(1) GENERAL INFORMATION:
(iii) NUMBER OF SEQUENCES: 101
(2) INFORMATION FOR SEQ ID NO:1:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 3496 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..3496
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
trascriptas
#e (mTRT) cDNA clone"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 10..3435
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA"
(ix) FEATURE:
(A) NAME/KEY: CDS
(B) LOCATION: 39..3404
(D) OTHER INFORMATION:
#/product= "mouse telomerase reverse
transcripta
#se (mTRT)"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:1:
GAATTCCGGG TGGGAGGCCC ATCCCGGCCT TGAGCACA ATG ACC CGC
# GCT CCT 53
#
# Met Thr Arg Ala Pro
#
# 1
# 5
CGT TGC CCC GCG GTG CGC TCT CTG CTG CGC A
#GC CGA TAC CGG GAG GTG 101
Arg Cys Pro Ala Val Arg Ser Leu Leu Arg S
#er Arg Tyr Arg Glu Val
10
# 15
# 20
TGG CCG CTG GCA ACC TTT GTG CGG CGC CTG G
#GG CCC GAG GGC AGG CGG 149
Trp Pro Leu Ala Thr Phe Val Arg Arg Leu G
#ly Pro Glu Gly Arg Arg
25
# 30
# 35
CTT GTG CAA CCC GGG GAC CCG AAG ATC TAC C
#GC ACT TTG GTT GCC CAA 197
Leu Val Gln Pro Gly Asp Pro Lys Ile Tyr A
#rg Thr Leu Val Ala Gln
40
# 45
# 50
TGC CTA GTG TGC ATG CAC TGG GGC TCA CAG C
#CT CCA CCT GCC GAC CTT 245
Cys Leu Val Cys Met His Trp Gly Ser Gln P
#ro Pro Pro Ala Asp Leu
55
# 60
# 65
TCC TTC CAC CAG GTG TCA TCC CTG AAA GAG C
#TG GTG GCC AGG GTT GTG 293
Ser Phe His Gln Val Ser Ser Leu Lys Glu L
#eu Val Ala Arg Val Val
70
# 75
# 80
# 85
CAG AGA CTC TGC GAG CGC AAC GAG AGA AAC G
#TG CTG GCT TTT GGC TTT 341
Gln Arg Leu Cys Glu Arg Asn Glu Arg Asn V
#al Leu Ala Phe Gly Phe
90
# 95
# 100
GAG CTG CTT AAC GAG GCC AGA GGC GGG CCT C
#CC ATG GCC TTC ACT AGT 389
Glu Leu Leu Asn Glu Ala Arg Gly Gly Pro P
#ro Met Ala Phe Thr Ser
105
# 110
# 115
AGC GTG CGT AGC TAC TTG CCC AAC ACT GTT A
#TT GAG ACC CTG CGT GTC 437
Ser Val Arg Ser Tyr Leu Pro Asn Thr Val I
#le Glu Thr Leu Arg Val
120
# 125
# 130
AGT GGT GCA TGG ATG CTA CTG TTG AGC CGA G
#TG GGC GAC GAC CTG CTG 485
Ser Gly Ala Trp Met Leu Leu Leu Ser Arg V
#al Gly Asp Asp Leu Leu
135
# 140
# 145
GTC TAC CTG CTG GCA CAC TGT GCT CTT TAT C
#TT CTG GTG CCC CCC AGC 533
Val Tyr Leu Leu Ala His Cys Ala Leu Tyr L
#eu Leu Val Pro Pro Ser
150
#155
#160
#165
TGT GCC TAC CAG GTG TGT GGG TCT CCC CTG T
#AC CAA ATT TGT GCC ACC 581
Cys Ala Tyr Gln Val Cys Gly Ser Pro Leu T
#yr Gln Ile Cys Ala Thr
170
# 175
# 180
ACG GAT ATC TGG CCC TCT GTG TCC GCT AGT T
#AC AGG CCC ACC CGA CCC 629
Thr Asp Ile Trp Pro Ser Val Ser Ala Ser T
#yr Arg Pro Thr Arg Pro
185
# 190
# 195
GTG GGC AGG AAT TTC ACT AAC CTT AGG TTC T
#TA CAA CAG ATC AAG AGC 677
Val Gly Arg Asn Phe Thr Asn Leu Arg Phe L
#eu Gln Gln Ile Lys Ser
200
# 205
# 210
AGT AGT CGC CAG GAA GCA CCG AAA CCC CTG G
#CC TTG CCA TCT CGA GGT 725
Ser Ser Arg Gln Glu Ala Pro Lys Pro Leu A
#la Leu Pro Ser Arg Gly
215
# 220
# 225
ACA AAG AGG CAT CTG AGT CTC ACC AGT ACA A
#GT GTG CCT TCA GCT AAG 773
Thr Lys Arg His Leu Ser Leu Thr Ser Thr S
#er Val Pro Ser Ala Lys
230
#235
#240
#245
AAG GCC AGA TGC TAT CCT GTC CCG AGA GTG G
#AG GAG GGA CCC CAC AGG 821
Lys Ala Arg Cys Tyr Pro Val Pro Arg Val G
#lu Glu Gly Pro His Arg
250
# 255
# 260
CAG GTG CTA CCA ACC CCA TCA GGC AAA TCA T
#GG GTG CCA AGT CCT GCT 869
Gln Val Leu Pro Thr Pro Ser Gly Lys Ser T
#rp Val Pro Ser Pro Ala
265
# 270
# 275
CGG TCC CCC GAG GTG CCT ACT GCA GAG AAA G
#AT TTG TCT TCT AAA GGA 917
Arg Ser Pro Glu Val Pro Thr Ala Glu Lys A
#sp Leu Ser Ser Lys Gly
280
# 285
# 290
AAG GTG TCT GAC CTG AGT CTC TCT GGG TCG G
#TG TGC TGT AAA CAC AAG 965
Lys Val Ser Asp Leu Ser Leu Ser Gly Ser V
#al Cys Cys Lys His Lys
295
# 300
# 305
CCC AGC TCC ACA TCT CTG CTG TCA CCA CCC C
#GC CAA AAT GCC TTT CAG 1013
Pro Ser Ser Thr Ser Leu Leu Ser Pro Pro A
#rg Gln Asn Ala Phe Gln
310
#315
#320
#325
CTC AGG CCA TTT ATT GAG ACC AGA CAT TTC C
#TT TAC TCC AGG GGA GAT 1061
Leu Arg Pro Phe Ile Glu Thr Arg His Phe L
#eu Tyr Ser Arg Gly Asp
330
# 335
# 340
GGC CAA GAG CGT CTA AAC CCC TCA TTC CTA C
#TC AGC AAC CTC CAG CCT 1109
Gly Gln Glu Arg Leu Asn Pro Ser Phe Leu L
#eu Ser Asn Leu Gln Pro
345
# 350
# 355
AAC TTG ACT GGG GCC AGG AGA CTG GTG GAG A
#TC ATC TTT CTG GGC TCA 1157
Asn Leu Thr Gly Ala Arg Arg Leu Val Glu I
#le Ile Phe Leu Gly Ser
360
# 365
# 370
AGG CCT AGG ACA TCA GGA CCA CTC TGC AGG A
#CA CAC CGT CTA TCG CGT 1205
Arg Pro Arg Thr Ser Gly Pro Leu Cys Arg T
#hr His Arg Leu Ser Arg
375
# 380
# 385
CGA TAC TGG CAG ATG CGG CCC CTG TTC CAA C
#AG CTG CTG GTG AAC CAT 1253
Arg Tyr Trp Gln Met Arg Pro Leu Phe Gln G
#ln Leu Leu Val Asn His
390
#395
#400
#405
GCA GAG TGC CAA TAT GTC AGA CTC CTC AGG T
#CA CAT TGC AGG TTT CGA 1301
Ala Glu Cys Gln Tyr Val Arg Leu Leu Arg S
#er His Cys Arg Phe Arg
410
# 415
# 420
ACA GCA AAC CAA CAG GTG ACA GAT GCC TTG A
#AC ACC AGC CCA CCG CAC 1349
Thr Ala Asn Gln Gln Val Thr Asp Ala Leu A
#sn Thr Ser Pro Pro His
425
# 430
# 435
CTC ATG GAT TTG CTC CGC CTG CAC AGC AGT C
#CC TGG CAG GTA TAT GGT 1397
Leu Met Asp Leu Leu Arg Leu His Ser Ser P
#ro Trp Gln Val Tyr Gly
440
# 445
# 450
TTT CTT CGG GCC TGT CTC TGC AAG GTG GTG T
#CT GCT AGT CTC TGG GGT 1445
Phe Leu Arg Ala Cys Leu Cys Lys Val Val S
#er Ala Ser Leu Trp Gly
455
# 460
# 465
ACC AGG CAC AAT GAG CGC CGC TTC TTT AAG A
#AC TTA AAG AAG TTC ATC 1493
Thr Arg His Asn Glu Arg Arg Phe Phe Lys A
#sn Leu Lys Lys Phe Ile
470
#475
#480
#485
TCG TTG GGG AAA TAC GGC AAG CTA TCA CTG C
#AG GAA CTG ATG TGG AAG 1541
Ser Leu Gly Lys Tyr Gly Lys Leu Ser Leu G
#ln Glu Leu Met Trp Lys
490
# 495
# 500
ATG AAA GTA GAG GAT TGC CAC TGG CTC CGC A
#GC AGC CCG GGG AAG GAC 1589
Met Lys Val Glu Asp Cys His Trp Leu Arg S
#er Ser Pro Gly Lys Asp
505
# 510
# 515
CGT GTC CCC GCT GCA GAG CAC CGT CTG AGG G
#AG AGG ATC CTG GCT ACG 1637
Arg Val Pro Ala Ala Glu His Arg Leu Arg G
#lu Arg Ile Leu Ala Thr
520
# 525
# 530
TTC CTG TTC TGG CTG ATG GAC ACA TAC GTG G
#TA CAG CTG CTT AGG TCA 1685
Phe Leu Phe Trp Leu Met Asp Thr Tyr Val V
#al Gln Leu Leu Arg Ser
535
# 540
# 545
TTC TTT TAC ATC ACA GAG AGC ACA TTC CAG A
#AG AAC AGG CTC TTC TTC 1733
Phe Phe Tyr Ile Thr Glu Ser Thr Phe Gln L
#ys Asn Arg Leu Phe Phe
550
#555
#560
#565
TAC CGT AAG AGT GTG TGG AGC AAG CTG CAG A
#GC ATT GGA GTC AGG CAA 1781
Tyr Arg Lys Ser Val Trp Ser Lys Leu Gln S
#er Ile Gly Val Arg Gln
570
# 575
# 580
CAC CTT GAG AGA GTG CGG CTA CGG GAG CTG T
#CA CAA GAG GAG GTC AGG 1829
His Leu Glu Arg Val Arg Leu Arg Glu Leu S
#er Gln Glu Glu Val Arg
585
# 590
# 595
CAT CAC CAG GAC ACC TGG CTA GCC ATG CCC A
#TC TGC AGA CTG CGC TTC 1877
His His Gln Asp Thr Trp Leu Ala Met Pro I
#le Cys Arg Leu Arg Phe
600
# 605
# 610
ATC CCC AAG CCC AAC GGC CTG CGG CCC ATT G
#TG AAC ATG AGT TAT AGC 1925
Ile Pro Lys Pro Asn Gly Leu Arg Pro Ile V
#al Asn Met Ser Tyr Ser
615
# 620
# 625
ATG GGT ACC AGA GCT TTG GGC AGA AGG AAG C
#AG GCC CAG CAT TTC ACC 1973
Met Gly Thr Arg Ala Leu Gly Arg Arg Lys G
#ln Ala Gln His Phe Thr
630
#635
#640
#645
CAG CGT CTC AAG ACT CTC TTC AGC ATG CTC A
#AC TAT GAG CGG ACA AAA 2021
Gln Arg Leu Lys Thr Leu Phe Ser Met Leu A
#sn Tyr Glu Arg Thr Lys
650
# 655
# 660
CAT CCT CAC CTT ATG GGG TCT TCT GTA CTG G
#GT ATG AAT GAC ATC TAC 2069
His Pro His Leu Met Gly Ser Ser Val Leu G
#ly Met Asn Asp Ile Tyr
665
# 670
# 675
AGG ACC TGG CGG GCC TTT GTG CTG CGT GTG C
#GT GCT CTG GAC CAG ACA 2117
Arg Thr Trp Arg Ala Phe Val Leu Arg Val A
#rg Ala Leu Asp Gln Thr
680
# 685
# 690
CCC AGG ATG TAC TTT GTT AAG GCA GAT GTG A
#CC GGG GCC TAT GAT GCC 2165
Pro Arg Met Tyr Phe Val Lys Ala Asp Val T
#hr Gly Ala Tyr Asp Ala
695
# 700
# 705
ATC CCC CAG GGT AAG CTG GTG GAG GTT GTT G
#CC AAT ATG ATC AGG CAC 2213
Ile Pro Gln Gly Lys Leu Val Glu Val Val A
#la Asn Met Ile Arg His
710
#715
#720
#725
TCG GAG AGC ACG TAC TGT ATC CGC CAG TAT G
#CA GTG GTC CGG AGA GAT 2261
Ser Glu Ser Thr Tyr Cys Ile Arg Gln Tyr A
#la Val Val Arg Arg Asp
730
# 735
# 740
AGC CAA GGC CAA GTC CAC AAG TCC TTT AGG A
#GA CAG GTC ACC ACC CTC 2309
Ser Gln Gly Gln Val His Lys Ser Phe Arg A
#rg Gln Val Thr Thr Leu
745
# 750
# 755
TCT GAC CTC CAG CCA TAC ATG GGC CAG TTC C
#TT AAG CAT CTG CAG GAT 2357
Ser Asp Leu Gln Pro Tyr Met Gly Gln Phe L
#eu Lys His Leu Gln Asp
760
# 765
# 770
TCA GAT GCC AGT GCA CTG AGG AAC TCC GTT G
#TC ATC GAG CAG AGC ATC 2405
Ser Asp Ala Ser Ala Leu Arg Asn Ser Val V
#al Ile Glu Gln Ser Ile
775
# 780
# 785
TCT ATG AAT GAG AGC AGC AGC AGC CTG TTT G
#AC TTC TTC CTG CAC TTC 2453
Ser Met Asn Glu Ser Ser Ser Ser Leu Phe A
#sp Phe Phe Leu His Phe
790
#795
#800
#805
CTG CGT CAC AGT GTC GTA AAG ATT GGT GAC A
#GG TGC TAT ACG CAG TGC 2501
Leu Arg His Ser Val Val Lys Ile Gly Asp A
#rg Cys Tyr Thr Gln Cys
810
# 815
# 820
CAG GGC ATC CCC CAG GGC TCC AGC CTA TCC A
#CC CTG CTC TGC AGT CTG 2549
Gln Gly Ile Pro Gln Gly Ser Ser Leu Ser T
#hr Leu Leu Cys Ser Leu
825
# 830
# 835
TGT TTC GGA GAC ATG GAG AAC AAG CTG TTT G
#CT GAG GTG CAG CGG GAT 2597
Cys Phe Gly Asp Met Glu Asn Lys Leu Phe A
#la Glu Val Gln Arg Asp
840
# 845
# 850
GGG TTG CTT TTA CGT TTT GTT GAT GAC TTT C
#TG TTG GTG ACG CCT CAC 2645
Gly Leu Leu Leu Arg Phe Val Asp Asp Phe L
#eu Leu Val Thr Pro His
855
# 860
# 865
TTG GAC CAA GCA AAA ACC TTC CTC AGC ACC C
#TG GTC CAT GGC GTT CCT 2693
Leu Asp Gln Ala Lys Thr Phe Leu Ser Thr L
#eu Val His Gly Val Pro
870
#875
#880
#885
GAG TAT GGG TGC ATG ATA AAC TTG CAG AAG A
#CA GTG GTG AAC TTC CCT 2741
Glu Tyr Gly Cys Met Ile Asn Leu Gln Lys T
#hr Val Val Asn Phe Pro
890
# 895
# 900
GTG GAG CCT GGT ACC CTG GGT GGT GCA GCT C
#CA TAC CAG CTG CCT GCT 2789
Val Glu Pro Gly Thr Leu Gly Gly Ala Ala P
#ro Tyr Gln Leu Pro Ala
905
# 910
# 915
CAC TGC CTG TTT CCC TGG TGT GGC TTG CTG C
#TG GAC ACT CAG ACT TTG 2837
His Cys Leu Phe Pro Trp Cys Gly Leu Leu L
#eu Asp Thr Gln Thr Leu
920
# 925
# 930
GAG GTG TTC TGT GAC TAC TCA GGT TAT GCC C
#AG ACC TCA ATT AAG ACG 2885
Glu Val Phe Cys Asp Tyr Ser Gly Tyr Ala G
#ln Thr Ser Ile Lys Thr
935
# 940
# 945
AGC CTC ACC TTC CAG AGT GTC TTC AAA GCT G
#GG AAG ACC ATG CGG AAC 2933
Ser Leu Thr Phe Gln Ser Val Phe Lys Ala G
#ly Lys Thr Met Arg Asn
950
#955
#960
#965
AAG CTC CTG TCG GTC TTG CGG TTG AAG TGT C
#AC GGT CTA TTT CTA GAC 2981
Lys Leu Leu Ser Val Leu Arg Leu Lys Cys H
#is Gly Leu Phe Leu Asp
970
# 975
# 980
TTG CAG GTG AAC AGC CTC CAG ACA GTC TGC A
#TC AAT ATA TAC AAG ATC 3029
Leu Gln Val Asn Ser Leu Gln Thr Val Cys I
#le Asn Ile Tyr Lys Ile
985
# 990
# 995
TTC CTG CTT CAG GCC TAC AGG TTC CAT GCA T
#GT GTG ATT CAG CTT CCC 3077
Phe Leu Leu Gln Ala Tyr Arg Phe His Ala C
#ys Val Ile Gln Leu Pro
1000
# 1005
# 1010
TTT GAC CAG CGT GTT AGG AAG AAC CTC ACA T
#TC TTT CTG GGC ATC ATC 3125
Phe Asp Gln Arg Val Arg Lys Asn Leu Thr P
#he Phe Leu Gly Ile Ile
1015
# 1020
# 1025
TCC AGC CAA GCA TCC TGC TGC TAT GCT ATC C
#TG AAG GTC AAG AAT CCA 3173
Ser Ser Gln Ala Ser Cys Cys Tyr Ala Ile L
#eu Lys Val Lys Asn Pro
1030 103
#5 1040
# 1045
GGA ATG ACA CTA AAG GCC TCT GGC TCC TTT C
#CT CCT GAA GCC GCA CAT 3221
Gly Met Thr Leu Lys Ala Ser Gly Ser Phe P
#ro Pro Glu Ala Ala His
1050
# 1055
# 1060
TGG CTC TGC TAC CAG GCC TTC CTG CTC AAG C
#TG GCT GCT CAT TCT GTC 3269
Trp Leu Cys Tyr Gln Ala Phe Leu Leu Lys L
#eu Ala Ala His Ser Val
1065
# 1070
# 1075
ATC TAC AAA TGT CTC CTG GGA CCT CTG AGG A
#CA GCC CAA AAA CTG CTG 3317
Ile Tyr Lys Cys Leu Leu Gly Pro Leu Arg T
#hr Ala Gln Lys Leu Leu
1080
# 1085
# 1090
TGC CGG AAG CTC CCA GAG GCG ACA ATG ACC A
#TC CTT AAA GCT GCA GCT 3365
Cys Arg Lys Leu Pro Glu Ala Thr Met Thr I
#le Leu Lys Ala Ala Ala
1095
# 1100
# 1105
GAC CCA GCC CTA AGC ACA GAC TTT CAG ACC A
#TT TTG GAC TAACCCTGTC 3414
Asp Pro Ala Leu Ser Thr Asp Phe Gln Thr I
#le Leu Asp
1110 111
#5 1120
TCCTTCCGCT AGATGAACAT GAAGGGCGAA TTCCAGCACA CTGGCGGCCG T
#TACTAGTGG 3474
ATCCGAGCTC GGTACCAAGC TT
#
# 3496
(2) INFORMATION FOR SEQ ID NO:2:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1122 amino
# acids
(B) TYPE: amino acid
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: protein
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:2:
Met Thr Arg Ala Pro Arg Cys Pro Ala Val A
#rg Ser Leu Leu Arg Ser
1 5
# 10
# 15
Arg Tyr Arg Glu Val Trp Pro Leu Ala Thr P
#he Val Arg Arg Leu Gly
20
# 25
# 30
Pro Glu Gly Arg Arg Leu Val Gln Pro Gly A
#sp Pro Lys Ile Tyr Arg
35
# 40
# 45
Thr Leu Val Ala Gln Cys Leu Val Cys Met H
#is Trp Gly Ser Gln Pro
50
# 55
# 60
Pro Pro Ala Asp Leu Ser Phe His Gln Val S
#er Ser Leu Lys Glu Leu
65
# 70
# 75
# 80
Val Ala Arg Val Val Gln Arg Leu Cys Glu A
#rg Asn Glu Arg Asn Val
85
# 90
# 95
Leu Ala Phe Gly Phe Glu Leu Leu Asn Glu A
#la Arg Gly Gly Pro Pro
100
# 105
# 110
Met Ala Phe Thr Ser Ser Val Arg Ser Tyr L
#eu Pro Asn Thr Val Ile
115
# 120
# 125
Glu Thr Leu Arg Val Ser Gly Ala Trp Met L
#eu Leu Leu Ser Arg Val
130
# 135
# 140
Gly Asp Asp Leu Leu Val Tyr Leu Leu Ala H
#is Cys Ala Leu Tyr Leu
145
#150
#155
#160
Leu Val Pro Pro Ser Cys Ala Tyr Gln Val C
#ys Gly Ser Pro Leu Tyr
165
# 170
# 175
Gln Ile Cys Ala Thr Thr Asp Ile Trp Pro S
#er Val Ser Ala Ser Tyr
180
# 185
# 190
Arg Pro Thr Arg Pro Val Gly Arg Asn Phe T
#hr Asn Leu Arg Phe Leu
195
# 200
# 205
Gln Gln Ile Lys Ser Ser Ser Arg Gln Glu A
#la Pro Lys Pro Leu Ala
210
# 215
# 220
Leu Pro Ser Arg Gly Thr Lys Arg His Leu S
#er Leu Thr Ser Thr Ser
225
#230
#235
#240
Val Pro Ser Ala Lys Lys Ala Arg Cys Tyr P
#ro Val Pro Arg Val Glu
245
# 250
# 255
Glu Gly Pro His Arg Gln Val Leu Pro Thr P
#ro Ser Gly Lys Ser Trp
260
# 265
# 270
Val Pro Ser Pro Ala Arg Ser Pro Glu Val P
#ro Thr Ala Glu Lys Asp
275
# 280
# 285
Leu Ser Ser Lys Gly Lys Val Ser Asp Leu S
#er Leu Ser Gly Ser Val
290
# 295
# 300
Cys Cys Lys His Lys Pro Ser Ser Thr Ser L
#eu Leu Ser Pro Pro Arg
305
#310
#315
#320
Gln Asn Ala Phe Gln Leu Arg Pro Phe Ile G
#lu Thr Arg His Phe Leu
325
# 330
# 335
Tyr Ser Arg Gly Asp Gly Gln Glu Arg Leu A
#sn Pro Ser Phe Leu Leu
340
# 345
# 350
Ser Asn Leu Gln Pro Asn Leu Thr Gly Ala A
#rg Arg Leu Val Glu Ile
355
# 360
# 365
Ile Phe Leu Gly Ser Arg Pro Arg Thr Ser G
#ly Pro Leu Cys Arg Thr
370
# 375
# 380
HisArg Leu Ser Arg Arg Tyr Trp Gln Met A
#rg Pro Leu Phe Gln Gln
385
#390
#395
#400
Leu Leu Val Asn His Ala Glu Cys Gln Tyr V
#al Arg Leu Leu Arg Ser
405
# 410
# 415
His Cys Arg Phe Arg Thr Ala Asn Gln Gln V
#al Thr Asp Ala Leu Asn
420
# 425
# 430
Thr Ser Pro Pro His Leu Met Asp Leu Leu A
#rg Leu His Ser Ser Pro
435
# 440
# 445
Trp Gln Val Tyr Gly Phe Leu Arg Ala Cys L
#eu Cys Lys Val Val Ser
450
# 455
# 460
Ala Ser Leu Trp Gly Thr Arg His Asn Glu A
#rg Arg Phe Phe Lys Asn
465
#470
#475
#480
Leu Lys Lys Phe Ile Ser Leu Gly Lys Tyr G
#ly Lys Leu Ser Leu Gln
485
# 490
# 495
Glu Leu Met Trp Lys Met Lys Val Glu Asp C
#ys His Trp Leu Arg Ser
500
# 505
# 510
Ser Pro Gly Lys Asp Arg Val Pro Ala Ala G
#lu His Arg Leu Arg Glu
515
# 520
# 525
Arg Ile Leu Ala Thr Phe Leu Phe Trp Leu M
#et Asp Thr Tyr Val Val
530
# 535
# 540
Gln Leu Leu Arg Ser Phe Phe Tyr Ile Thr G
#lu Ser Thr Phe Gln Lys
545
#550
#555
#560
Asn Arg Leu Phe Phe Tyr Arg Lys Ser Val T
#rp Ser Lys Leu Gln Ser
565
# 570
# 575
Ile Gly Val Arg Gln His Leu Glu Arg Val A
#rg Leu Arg Glu Leu Ser
580
# 585
# 590
Gln Glu Glu Val Arg His His Gln Asp Thr T
#rp Leu Ala Met Pro Ile
595
# 600
# 605
Cys Arg Leu Arg Phe Ile Pro Lys Pro Asn G
#ly Leu Arg Pro Ile Val
610
# 615
# 620
Asn Met Ser Tyr Ser Met Gly Thr Arg Ala L
#eu Gly Arg Arg Lys Gln
625
#630
#635
#640
Ala Gln His Phe Thr Gln Arg Leu Lys Thr L
#eu Phe Ser Met Leu Asn
645
# 650
# 655
Tyr Glu Arg Thr Lys His Pro His Leu Met G
#ly Ser Ser Val Leu Gly
660
# 665
# 670
Met Asn Asp Ile Tyr Arg Thr Trp Arg Ala P
#he Val Leu Arg Val Arg
675
# 680
# 685
Ala Leu Asp Gln Thr Pro Arg Met Tyr Phe V
#al Lys Ala Asp Val Thr
690
# 695
# 700
Gly Ala Tyr Asp Ala Ile Pro Gln Gly Lys L
#eu Val Glu Val Val Ala
705
#710
#715
#720
Asn Met Ile Arg His Ser Glu Ser Thr Tyr C
#ys Ile Arg Gln Tyr Ala
725
# 730
# 735
Val Val Arg Arg Asp Ser Gln Gly Gln Val H
#is Lys Ser Phe Arg Arg
740
# 745
# 750
Gln Val Thr Thr Leu Ser Asp Leu Gln Pro T
#yr Met Gly Gln Phe Leu
755
# 760
# 765
Lys His Leu Gln Asp Ser Asp Ala Ser Ala L
#eu Arg Asn Ser Val Val
770
# 775
# 780
Ile Glu Gln Ser Ile Ser Met Asn Glu Ser S
#er Ser Ser Leu Phe Asp
785
#790
#795
#800
Phe Phe Leu His Phe Leu Arg His Ser Val V
#al Lys Ile Gly Asp Arg
805
# 810
# 815
Cys Tyr Thr Gln Cys Gln Gly Ile Pro Gln G
#ly Ser Ser Leu Ser Thr
820
# 825
# 830
Leu Leu Cys Ser Leu Cys Phe Gly Asp Met G
#lu Asn Lys Leu Phe Ala
835
# 840
# 845
Glu Val Gln Arg Asp Gly Leu Leu Leu Arg P
#he Val Asp Asp Phe Leu
850
# 855
# 860
Leu Val Thr Pro His Leu Asp Gln Ala Lys T
#hr Phe Leu Ser Thr Leu
865
#870
#875
#880
Val His Gly Val Pro Glu Tyr Gly Cys Met I
#le Asn Leu Gln Lys Thr
885
# 890
# 895
Val Val Asn Phe Pro Val Glu Pro Gly Thr L
#eu Gly Gly Ala Ala Pro
900
# 905
# 910
Tyr Gln Leu Pro Ala His Cys Leu Phe Pro T
#rp Cys Gly Leu Leu Leu
915
# 920
# 925
Asp Thr Gln Thr Leu Glu Val Phe Cys Asp T
#yr Ser Gly Tyr Ala Gln
930
# 935
# 940
Thr Ser Ile Lys Thr Ser Leu Thr Phe Gln S
#er Val Phe Lys Ala Gly
945
#950
#955
#960
Lys Thr Met Arg Asn Lys Leu Leu Ser Val L
#eu Arg Leu Lys Cys His
965
# 970
# 975
Gly Leu Phe Leu Asp Leu Gln Val Asn Ser L
#eu Gln Thr Val Cys Ile
980
# 985
# 990
Asn Ile Tyr Lys Ile Phe Leu Leu Gln Ala T
#yr Arg Phe His Ala Cys
995
# 1000
# 1005
Val Ile Gln Leu Pro Phe Asp Gln Arg Val A
#rg Lys Asn Leu Thr Phe
1010
# 1015
# 1020
Phe Leu Gly Ile Ile Ser Ser Gln Ala Ser C
#ys Cys Tyr Ala Ile Leu
1025 103
#0 1035
# 1040
Lys Val Lys Asn Pro Gly Met Thr Leu Lys A
#la Ser Gly Ser Phe Pro
1045
# 1050
# 1055
Pro Glu Ala Ala His Trp Leu Cys Tyr Gln A
#la Phe Leu Leu Lys Leu
1060
# 1065
# 1070
Ala Ala His Ser Val Ile Tyr Lys Cys Leu L
#eu Gly Pro Leu Arg Thr
1075
# 1080
# 1085
Ala Gln Lys Leu Leu Cys Arg Lys Leu Pro G
#lu Ala Thr Met Thr Ile
1090
# 1095
# 1100
Leu Lys Ala Ala Ala Asp Pro Ala Leu Ser T
#hr Asp Phe Gln Thr Ile
1105 111
#0 1115
# 1120
Leu Asp
(2) INFORMATION FOR SEQ ID NO:3:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1132 amino
# acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: protein
(ix) FEATURE:
(A) NAME/KEY: Protein
(B) LOCATION: 1..1132
(D) OTHER INFORMATION:
#/note= "human telomerase reverse
transcripta
#se (hTRT)"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:3:
Met Pro Arg Ala Pro Arg Cys Arg Ala Val A
#rg Ser Leu Leu Arg Ser
1 5
# 10
# 15
His Tyr Arg Glu Val Leu Pro Leu Ala Thr P
#he Val Arg Arg Leu Gly
20
# 25
# 30
Pro Gln Gly Trp Arg Leu Val Gln Arg Gly A
#sp Pro Ala Ala Phe Arg
35
# 40
# 45
Ala Leu Val Ala Gln Cys Leu Val Cys Val P
#ro Trp Asp Ala Arg Pro
50
# 55
# 60
Pro Pro Ala Ala Pro Ser Phe Arg Gln Val S
#er Cys Leu Lys Glu Leu
65
#70
#75
#80
Val Ala Arg Val Leu Gln Arg Leu Cys Glu A
#rg Gly Ala Lys Asn Val
85
# 90
# 95
Leu Ala Phe Gly Phe Ala Leu Leu Asp Gly A
#la Arg Gly Gly Pro Pro
100
# 105
# 110
Glu Ala Phe Thr Thr Ser Val Arg Ser Tyr L
#eu Pro Asn Thr Val Thr
115
# 120
# 125
Asp Ala Leu Arg Gly Ser Gly Ala Trp Gly L
#eu Leu Leu Arg Arg Val
130
# 135
# 140
Gly Asp Asp Val Leu Val His Leu Leu Ala A
#rg Cys Ala Leu Phe Val
145
#150
#155
#160
Leu Val Ala Pro Ser Cys Ala Tyr Gln Val C
#ys Gly Pro Pro Leu Tyr
165
# 170
# 175
Gln Leu Gly Ala Ala Thr Gln Ala Arg Pro P
#ro Pro His Ala Ser Gly
180
# 185
# 190
Pro Arg Arg Arg Leu Gly Cys Glu Arg Ala T
#rp Asn His Ser Val Arg
195
# 200
# 205
Glu Ala Gly Val Pro Leu Gly Leu Pro Ala P
#ro Gly Ala Arg Arg Arg
210
# 215
# 220
Gly Gly Ser Ala Ser Arg Ser Leu Pro Leu P
#ro Lys Arg Pro Arg Arg
225
#230
#235
#240
Gly Ala Ala Pro Glu Pro Glu Arg Thr Pro V
#al Gly Gln Gly Ser Trp
245
# 250
# 255
Ala His Pro Gly Arg Thr Arg Gly Pro Ser A
#sp Arg Gly Phe Cys Val
260
# 265
# 270
Val Ser Pro Ala Arg Pro Ala Glu Glu Ala T
#hr Ser Leu Glu Gly Ala
275
# 280
# 285
Leu Ser Gly Thr Arg His Ser His Pro Ser V
#al Gly Arg Gln His His
290
# 295
# 300
Ala Gly Pro Pro Ser Thr Ser Arg Pro Pro A
#rg Pro Trp Asp Thr Pro
305
#310
#315
#320
Cys Pro Pro Val Tyr Ala Glu Thr Lys His P
#he Leu Tyr Ser Ser Gly
325
# 330
# 335
Asp Lys Glu Gln Leu Arg Pro Ser Phe Leu L
#eu Ser Ser Leu Arg Pro
340
# 345
# 350
Ser Leu Thr Gly Ala Arg Arg Leu Val Glu T
#hr Ile Phe Leu Gly Ser
355
# 360
# 365
Arg Pro Trp Met Pro Gly Thr Pro Arg Arg L
#eu Pro Arg Leu Pro Gln
370
# 375
# 380
Arg Tyr Trp Gln Met Arg Pro Leu Phe Leu G
#lu Leu Leu Gly Asn His
385
#390
#395
#400
Ala Gln Cys Pro Tyr Gly Val Leu Leu Lys T
#hr His Cys Pro Leu Arg
405
# 410
# 415
Ala Ala Val Thr Pro Ala Ala Gly Val Cys A
#la Arg Glu Lys Pro Gln
420
# 425
# 430
Gly Ser Val Ala Ala Pro Glu Glu Glu Asp T
#hr Asp Pro Arg Arg Leu
435
# 440
# 445
Val Gln Leu Leu Arg Gln His Ser Ser Pro T
#rp Gln Val Tyr Gly Phe
450
# 455
# 460
Val Arg Ala Cys Leu Arg Arg Leu Val Pro P
#ro Gly Leu Trp Gly Ser
465
#470
#475
#480
Arg His Asn Glu Arg Arg Phe Leu Arg Asn T
#hr Lys Lys Phe Ile Ser
485
# 490
# 495
Leu Gly Lys His Ala Lys Leu Ser Leu Gln G
#lu Leu Thr Trp Lys Met
500
# 505
# 510
Ser Val Arg Asp Cys Ala Trp Leu Arg Arg S
#er Pro Gly Val Gly Cys
515
# 520
# 525
Val Pro Ala Ala Glu His Arg Leu Arg Glu G
#lu Ile Leu Ala Lys Phe
530
# 535
# 540
Leu His Trp Leu Met Ser Val Tyr Val Val G
#lu Leu Leu Arg Ser Phe
545
#550
#555
#560
Phe Tyr Val Thr Glu Thr Thr Phe Gln Lys A
#sn Arg Leu Phe Phe Tyr
565
# 570
# 575
Arg Lys Ser Val Trp Ser Lys Leu Gln Ser I
#le Gly Ile Arg Gln His
580
# 585
# 590
Leu Lys Arg Val Gln Leu Arg Glu Leu Ser G
#lu Ala Glu Val Arg Gln
595
# 600
# 605
His Arg Glu Ala Arg Pro Ala Leu Leu Thr S
#er Arg Leu Arg Phe Ile
610
# 615
# 620
Pro Lys Pro Asp Gly Leu Arg Pro Ile Val A
#sn Met Asp Tyr Val Val
625
#630
#635
#640
Gly Ala Arg Thr Phe Arg Arg Glu Lys Arg A
#la Glu Arg Leu Thr Ser
645
# 650
# 655
Arg Val Lys Ala Leu Phe Ser Val Leu Asn T
#yr Glu Arg Ala Arg Arg
660
# 665
# 670
Pro Gly Leu Leu Gly Ala Ser Val Leu Gly L
#eu Asp Asp Ile His Arg
675
# 680
# 685
Ala Trp Arg Thr Phe Val Leu Arg Val Arg A
#la Gln Asp Pro Pro Pro
690
# 695
# 700
Glu Leu Tyr Phe Val Lys Val Asp Val Thr G
#ly Ala Tyr Asp Thr Ile
705
#710
#715
#720
Pro Gln Asp Arg Leu Thr Glu Val Ile Ala S
#er Ile Ile Lys Pro Gln
725
# 730
# 735
Asn Thr Tyr Cys Val Arg Arg Tyr Ala Val V
#al Gln Lys Ala Ala His
740
# 745
# 750
Gly His Val Arg Lys Ala Phe Lys Ser His V
#al Ser Thr Leu Thr Asp
755
# 760
# 765
Leu Gln Pro Tyr Met Arg Gln Phe Val Ala H
#is Leu Gln Glu Thr Ser
770
# 775
# 780
Pro Leu Arg Asp Ala Val Val Ile Glu Gln S
#er Ser Ser Leu Asn Glu
785
#790
#795
#800
Ala Ser Ser Gly Leu Phe Asp Val Phe Leu A
#rg Phe Met Cys His His
805
# 810
# 815
Ala Val Arg Ile Arg Gly Lys Ser Tyr Val G
#ln Cys Gln Gly Ile Pro
820
# 825
# 830
Gln Gly Ser Ile Leu Ser Thr Leu Leu Cys S
#er Leu Cys Tyr Gly Asp
835
# 840
# 845
Met Glu Asn Lys Leu Phe Ala Gly Ile Arg A
#rg Asp Gly Leu Leu Leu
850
# 855
# 860
Arg Leu Val Asp Asp Phe Leu Leu Val Thr P
#ro His Leu Thr His Ala
865
#870
#875
#880
Lys Thr Phe Leu Arg Thr Leu Val Arg Gly V
#al Pro Glu Tyr Gly Cys
885
# 890
# 895
Val Val Asn Leu Arg Lys Thr Val Val Asn P
#he Pro Val Glu Asp Glu
900
# 905
# 910
Ala Leu Gly Gly Thr Ala Phe Val Gln Met P
#ro Ala His Gly Leu Phe
915
# 920
# 925
Pro Trp Cys Gly Leu Leu Leu Asp Thr Arg T
#hr Leu Glu Val Gln Ser
930
# 935
# 940
Asp Tyr Ser Ser Tyr Ala Arg Thr Ser Ile A
#rg Ala Ser Leu Thr Phe
945
#950
#955
#960
Asn Arg Gly Phe Lys Ala Gly Arg Asn Met A
#rg Arg Lys Leu Phe Gly
965
# 970
# 975
Val Leu Arg Leu Lys Cys His Ser Leu Phe L
#eu Asp Leu Gln Val Asn
980
# 985
# 990
Ser Leu Gln Thr Val Cys Thr Asn Ile Tyr L
#ys Ile Leu Leu Leu Gln
995
# 1000
# 1005
Ala Tyr Arg Phe His Ala Cys Val Leu Gln L
#eu Pro Phe His Gln Gln
1010
# 1015
# 1020
Val Trp Lys Asn Pro Thr Phe Phe Leu Arg V
#al Ile Ser Asp Thr Ala
1025 103
#0 1035
# 1040
Ser Leu Cys Tyr Ser Ile Leu Lys Ala Lys A
#sn Ala Gly Met Ser Leu
1045
# 1050
# 1055
Gly Ala Lys Gly Ala Ala Gly Pro Leu Pro S
#er Glu Ala Val Gln Trp
1060
# 1065
# 1070
Leu Cys His Gln Ala Phe Leu Leu Lys Leu T
#hr Arg His Arg Val Thr
1075
# 1080
# 1085
Tyr Val Pro Leu Leu Gly Ser Leu Arg Thr A
#la Gln Thr Gln Leu Ser
1090
# 1095
# 1100
Arg Lys Leu Pro Gly Thr Thr Leu Thr Ala L
#eu Glu Ala Ala Ala Asn
1105 111
#0 1115
# 1120
Pro Ala Leu Pro Ser Asp Phe Lys Thr Ile L
#eu Asp
1125
# 1130
(2) INFORMATION FOR SEQ ID NO:4:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 1808 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..1808
(D) OTHER INFORMATION:
#/note= "preliminary sequence of genomic
mouse te
#lomerase reverse transcriptase
(mTRT) p
#romoter region"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 1680
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA start site"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 1709
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) ORF start site"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:4:
AAAGCAGGCC TGTAACACAA AGGTCCTTTT TCCTGGTTTA TCGTGGCTGG T
#AGACAATTT 60
CCACTTGTTT TCCACTTCAG TTTTTTCTAC TCGGTTGTTA TTGGATTCTG A
#TGCTTGAAC 120
CCAGGTTGGT AGTCAGCAAG TGCACCCCTT CCTTCTTTTT CTTGGTTTTT T
#TGAGGCAGG 180
TCTCATTTTG CCCAAGTGGA CCTAAATTTC AGCATGTAGT GGCTGGTTTN G
#AATGCTTTT 240
TCATCCTGCT NTACTTCCCA AGAGTAGCTA ACAAGTGTGC ACCACCATGC C
#CCGCGATAT 300
TTTTATTTTT GAGACTGTTT TCTATGCTGG TTTCTTTGGG GAACTACACT A
#AGGTAGCTT 360
ACAAGTGTGC ACCACCATGC CCCGCGATAT TCTTATTTTT GAGACTGTTT T
#CTATGCTGG 420
TTTCTTTGGG GAACTACACT AAGGTAGCTT CATTGTTGGC ATAAATTTCT C
#AGTTCAGGC 480
CCATATCTCT TAAGTAGCAG AACTAAGCCA AATCTTCAAA CAAACCCCTT C
#AAAAAGACT 540
GATGTCCACT AAACGGACTT CTAAAATAGC TCCCTGTAAT CCTGAGCATT T
#ACCAAGGCG 600
GCAGACTTCC TATAAGGGAG TAAATATGAA AACGCGCCTG TTCAAATGCT A
#GGTCGGTGG 660
ATAGAAGCAA TTTCCTCAGA AAGCTGAAGG CACCAAAGGT TATATTTGTT A
#GCATTTCAG 720
TGTTTGCCAA ACTCAGCTAC AGTAGAGATC ACAGATTCCC TATTTCCCAG A
#GATTCAAAA 780
TTCAGCAGCC CCTCTCTAAC TATGGCTCAG AGTCGTGTCA TTACATATGC C
#CCAACAACA 840
ACCCCCACCC CTATCCTACC CCCGCCTCAC ACGTGCAAGT ACTATCACAG T
#TGCCAACCT 900
AGCAGAGCTG CCATCCTAAG GTCGAGGTCG CCGCTTTGGC TGTGTGCACA G
#GCAAGCGCC 960
CTCACCCAAT GGCCCTGGCC TTGCTATGGG TGCGTGAGTT GAGATGATGC T
#CTGGACTCT 1020
GAGGTGAAGG CCACTGGAAC AGTGAAAAAA GCTAACGCAG GGCTTTTACC T
#AGGTCCCCT 1080
TCCTTTGGTG GTGGGTGTTT ACGGAACATA TTTGGGATCT GGAGTGTATG G
#TCGCACCAC 1140
AATAAAGCCT TAACCTATAT AGTAGAATGT TCAGCTGTAA TCATTAAGAA C
#TGAGATTGC 1200
CACCACCCAC CTCACTGTCT GTGTCAACCA CAGCAGGCTG GAGCAGTCAG C
#TCAGGAACA 1260
GGCAAAACCT TAGGTCCTCC GCCTACCTAA CCTTCAATAC ATCAAGGATA G
#GCTTCTTTG 1320
CTTGCCCAAA CCTCGCCCCA GTCTAGACCA CCTGGGGATT CCCAGCTCAG G
#GCGAAAAGG 1380
AAGCCCGAGA AGCATTCTGT AGAGGGAAAT CCTGCATGAG TGCGCCCCCT T
#TCGTTACTC 1440
CAACACATCC AGCAACCACT GAACTTGGCC GGGGAACACA CCTGGTCCTC A
#TGCACCAGC 1500
ATTGTGACCA TCAACGGAAA AGTACTATTG CTGCGACCCC GCCCCTTCCG C
#TACAACGCT 1560
TGGTCCGCCT GAATCCCGCC CCTTCCTCCG TTCCCAGCCT CATCTTTTTC G
#TCGTGGACT 1620
CTCAGTGGCC TGGGTCCTGG CTGTTTTCTA AGCACACCCT TGCATCTTGG T
#TCCCGCACG 1680
TGGGAGGCCC ATCCCGGCCT TGAGCACAAT GACCCGCGCT CCTCGTTGCC C
#CGCGGTGCG 1740
CTCTCTGCTG CGCAGCCGAT ACCGGGAGGT GTGGCCGCTG GCAACCTTTG T
#GCGGCGCCT 1800
GGGGCCCG
#
#
# 1808
(2) INFORMATION FOR SEQ ID NO:5:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 2651 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..2651
(D) OTHER INFORMATION:
#/note= "preliminary sequence of B2.18
containing
#the genomic promoter region
of mouse
# telomerase reverse
transcripta
#se (mTRT)"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 2057
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) cDNA start site"
(ix) FEATURE:
(A) NAME/KEY: misc_
#feature
(B) LOCATION: 2087
(D) OTHER INFORMATION:
#/note= "mouse telomerase reverse
transcripta
#se (mTRT) ORF start site"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:5:
AAACAAAGTC AATGAGGAAT GGCTGTGTTC CATCTTGACC ACTGAGAAGT A
#AAACCGGGT 60
GCAGTGATGT CCAAAAAGGC AAGGTGACAG CAGAGCGGAG GCCCCAATCT A
#GAGCAGGGC 120
CTTCGGTTTG AATGGGGGAG ATCAAACGGG AGTTGGTTTC TGCCAGCACG T
#TGGGGTAGA 180
AGGTGGAACA TGAAAGGTCC CCGAGGATTT CGAGAGTCCA TAGGGGTAGC G
#ACACCCGAG 240
GTCTTCTTTT TCACCTCCTT CCCTGCAGGG GAGATGACTT TTACCACAGT C
#GTTTATGGG 300
AAAGTTCCTA GGGGCAGCCC CTCCCCAAAA AGGCTCTCCC TGGCCTCATG T
#TTCAAAGCA 360
CAGCTTTTTA AAGCAGGCCT GTTAAGCACA AAGGATCCCG AATCCTGGCT T
#CATCGTTGG 420
CTGGTAGACA ACTTCCACTC GTTTTCCACT TCAGTTTCTT CTAACTCTGT T
#GTTATTTGA 480
TTCTGATGCT TGAACCCAGG GTTGTGTAGT CAGCAAGTGC TACCCCCTCC T
#CCTCTTCTT 540
TGTTTTTTTG AGGCAGGGTC TCATTTTGCC CAAGTGGACC TAAATTTCAG C
#ATGTAGCTG 600
GCCTGGTTTT GAATGCCTTC TCATCCTGCC TCTACTTCCC AAGAGTAGCT T
#ACAAGTGTG 660
CACCACCATG CCCCGCGATA TTCTTATTTT TGAGACTGTT TTCTATGCTG G
#TTTCTTTGG 720
GGAACTACAC TAAGGTAGCT TACAAGTGTG CACCACCATG CCCCGCGATA T
#TCTTATTTT 780
TGAGACTGTT TTCTATGCTG GTTTCTTTGG GGAACTACAC TAAGGTAGCT T
#CATTGTTGG 840
CATAAATTTC TCAGTTCAGG CCCATATCTC CTAAGTAGCA GAACTAAGCA A
#ATCTCAAAC 900
AAACCCCTCA AAAAGACTGA TGTCCACTAA ACGGACTTCT AAAATAGCTC C
#CTGTAATCC 960
TGAGCATTTA CAAGGCGGCA GACCTCCTAT AAGGGAGTAA ATATGAAAAC G
#CGCCTGTTC 1020
AAATGCTAGG TCGGTGGATA GAAGCAATTT CCTCAGAAAG CTGAAGGCAC C
#AAAGGTTAT 1080
ATTTGTTAGC ATTTCAGTGT TTGCCAAACT CAGCTACAGT AGAGATCACA G
#ATTCCCTAT 1140
TTCCCAGAGA TTCAAAATTC AGCAGCCCCT CTCTAACTAT GGCTCAGAGT C
#GTGTCATTA 1200
CATATGCCCC AACAACAACC CCCACCCCTA TCCTACCCCC GCCTCACACG T
#GCAAGTACT 1260
ATCACAGTTG CCAACCTAGC AGAGCTGCCA TCCTAAGGTC GAGGTCGCCG C
#TTTGGCTGT 1320
GTGCACAGGC AAGCGCCCTC ACCCAATGGC CCTGGCCTTG CTATGGGTGC G
#TGAGTTGAG 1380
ATGATGCTCT GGACTCTGAG GTGAAGGCCA CTGGAACAGT GAAAAAAGCT A
#ACGCAGGGC 1440
TTTTACCTAG GTCCCCTTCC TTTGGTGGTG GGTGTTTACG GAACATATTT G
#GGATCTGGA 1500
GTGTATGGTC GCACCACAAT AAAGCCTTAA CCTATATAGT AGAATTTCAG C
#TGTAATCAT 1560
TAAGAACTGA GATTGCCACC ACCCACCTCA CTGTCTGTGT CAACCACAGC A
#GGCTGGAGC 1620
AGTCAGCTCA GGAACAGGCA AAACCTTAGG TCCCTCCGCC TACCTAACCT T
#CAATACATC 1680
AAGGATAGGC TTCTTTGCTT GCCCAAACCT CGCCCCAGTC TAGACCACCT G
#GGGATTCCC 1740
AGCTCAGGGC GAAAAGGAAG CCCGAGAAGC ATTCTGTAGA GGGAAATCCT G
#CATGAGTGC 1800
GCCCCCTTTC GTTACTCCAA CACATCCAGC AACCACTGAA CTTGGCCGGG G
#AACACACCT 1860
GGTCCTCATG CACCAGCATT GTGACCATCA ACGGAAAAGT ACTATTGCTG C
#GACCCCGCC 1920
CCTTCCGCTA CAACGCTTGG TCCGCCTGAA TCCCGCCCCT TCCTCCGTTC C
#CAGCCTCAT 1980
CTTTTTCGTC GTGGACTCTC AGTGGCCTGG GTCCTGGCTG TTTTCTAAGC A
#CACCCTTGC 2040
ATCTTGGTTC CCGCACGTGG GAAGGCCCAT CCCGGCCTTG AGCACAATGA C
#CCGCGCTCC 2100
TCGTTGCCCC GCGGTGCGCT CTCTGCTGCG CAGCCGATAC CGGGAGGTGT G
#GCCGCTGGC 2160
AACCTTTGTG CGGCGCCTGG GGCCCGAGGG CAGGCGGCTT GTGCAACCCG G
#GGACCGAAG 2220
ATCTACCGCA CTTTGGGTTG CCCAATGCCT AGTGTGCATG CACTGGGGCT C
#ACAGCCTCC 2280
ACCTGCCGAC CTTTCCTTCC ACCAGGTGGG CCTCCAGGCG GGATCCCCAT G
#GGTCAGGGG 2340
CGGAAAGCCG GGAGGACGTG GGATAGTGCG TCTAGCTCAT GTGTCAAGAC C
#CTCTTCTCC 2400
TTACCAGGTG TCATCCCTGA AAAGAGCTGG TGGCCAGGGT TGTGCAGAGA C
#TCTGCGAGC 2460
GCAACGAGAG AAACGTGCTG GCTTTTGGCT TTGAGCTGCT TAACGAAGCC A
#GAAGCGGGC 2520
CTCCCATGGC CTTCACTAAT TAGCGTGCGT AAGCTACTTG CCCAACACTG T
#TATTGAAAA 2580
CCTGCGTGTC AGTGGTGCAT GGATGCTACT GTTGAGCCGA ATGGGCGACA C
#CTGCTGGTC 2640
TACCTGCTGG C
#
#
# 2651
(2) INFORMATION FOR SEQ ID NO:6:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 18 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..18
(D) OTHER INFORMATION:
#/note= "human telomerase reverse
transcripta
#se (hTRT) substrate oligonucleotide "TS""
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:6:
AATCCGTCGA GCAGAGTT
#
#
# 18
(2) INFORMATION FOR SEQ ID NO:7:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA (genomic)
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..6
(D) OTHER INFORMATION:
#/note= "human telomeric repeat"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:7:
TTAGGG
#
#
# 6
(2) INFORMATION FOR SEQ ID NO:8:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "3' primer hTRT.28"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:8:
CTCGGACCAG GGTCCTGAGG AA
#
# 22
(2) INFORMATION FOR SEQ ID NO:9:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 23 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..23
(D) OTHER INFORMATION:
#/note= "primer mTRT.35"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:9:
CTTCCTCAGG ACCCTGGTCC GAG
#
# 23
(2) INFORMATION FOR SEQ ID NO:10:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "primer mTRT.27"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:10:
ATTGAGGTCT GGGCATACCT GC
#
# 22
(2) INFORMATION FOR SEQ ID NO:11:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "3' primer encoding
carboxy-ter
#minus of hTRT"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:11:
TCAGCGTCGT CCCCGGGAGC TT
#
# 22
(2) INFORMATION FOR SEQ ID NO:12:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..22
(D) OTHER INFORMATION:
#/note= "5' primer from upstream
mTRT Ra-
#200"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:12:
TCACCCTCTG AGGCTTCGGT GT
#
# 22
(2) INFORMATION FOR SEQ ID NO:13:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 21 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..21
(D) OTHER INFORMATION:
#/note= "primer mTRT.10"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:13:
CGTCGATACT GGCAGATGCG G
#
#
#21
(2) INFORMATION FOR SEQ ID NO:14:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 24 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..24
(D) OTHER INFORMATION:
#/note= "primer mTRT.53"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:14:
GTGCTGAGGC TACAATGCCC ATGT
#
# 24
(2) INFORMATION FOR SEQ ID NO:15:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 21 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..21
(D) OTHER INFORMATION:
#/note= "5' primer mTRT.9"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:15:
CTTTTACATC ACAGAGAGCA C
#
#
#21
(2) INFORMATION FOR SEQ ID NO:16:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..25
(D) OTHER INFORMATION:
#/note= "primer mTRT.52"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:16:
CATGTTCATC TAGCGGAAGG AGACA
#
# 25
(2) INFORMATION FOR SEQ ID NO:17:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 33 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..33
(D) OTHER INFORMATION:
#/note= "mF550A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:17:
ACAGCTGCTT AGATCTTTCG CTTACATCAC AGA
#
# 33
(2) INFORMATION FOR SEQ ID NO:18:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..35
(D) OTHER INFORMATION:
#/note= "mD701A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:18:
TTGTTAAGGC AGCTGTGACC GGTGCCTATG ATGCC
#
# 35
(2) INFORMATION FOR SEQ ID NO:19:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 38 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..38
(D) OTHER INFORMATION:
#/note= "mD860A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:19:
TACGTTTTGT TGCTGACTTT CTACTAGTGA CGCCTCAC
#
# 38
(2) INFORMATION FOR SEQ ID NO:20:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 base
#pairs
(B) TYPE: nucleic acid
(C) STRANDEDNESS: single
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: DNA
(ix) FEATURE:
(A) NAME/KEY: -
(B) LOCATION: 1..38
(D) OTHER INFORMATION:
#/note= "mD600A oligo"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:20:
GGCATCACCA GGCCACGTGG CTGGCCATGC CCATC
#
# 35
(2) INFORMATION FOR SEQ ID NO:21:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:21:
Trp Leu Met Ser Val Tyr Val Val Glu Leu L
#eu Arg Ser Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Thr Thr Phe Gln Lys Asn Arg L
#eu Phe Phe Tyr Arg Lys
20
# 25
# 30
Ser Val Trp Ser Lys Leu Gln Ser Ile Gly I
#le Arg Gln His Leu Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:22:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 54 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:22:
Glu Val Arg Gln His Arg Glu Ala Arg Pro A
#la Leu Leu Thr Ser Arg
1 5
# 10
# 15
Leu Arg Phe Ile Pro Lys Pro Asp Gly Leu A
#rg Pro Ile Val Asn Met
20
# 25
# 30
Asp Tyr Val Val Gly Ala Arg Thr Phe Arg A
#rg Glu Lys Arg Ala Glu
35
# 40
# 45
Arg Leu Thr Ser Arg Val
50
(2) INFORMATION FOR SEQ ID NO:23:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:23:
Pro Pro Pro Glu Leu Tyr Phe Val Lys Val A
#sp Val Thr Gly Ala Tyr
1 5
# 10
# 15
Asp Thr Ile Pro Gln Asp Arg Leu Thr Glu V
#al Ile Ala Ser Ile Ile
20
# 25
# 30
Lys Pro
(2) INFORMATION FOR SEQ ID NO:24:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:24:
Lys Ser Tyr Val Gln Cys Gln Gly Ile Pro G
#ln Gly Ser Ile Leu Ser
1 5
# 10
# 15
Thr Leu Leu Cys Ser Leu Cys Tyr Gly Asp M
#et Glu Asn Lys Leu Phe
20
# 25
# 30
Ala Gly Ile
35
(2) INFORMATION FOR SEQ ID NO:25:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:25:
Leu Leu Arg Leu Val Asp Asp Phe Leu Leu V
#al Thr Pro His Leu Thr
1 5
# 10
# 15
His
(2) INFORMATION FOR SEQ ID NO:26:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:26:
Ala Lys Thr Phe Leu Arg Thr Leu Val Arg G
#ly Val Pro Glu Tyr Gly
1 5
# 10
# 15
Cys Val Val Asn Leu Arg Lys Thr Val Val
20
# 25
(2) INFORMATION FOR SEQ ID NO:27:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:27:
His Gly Leu Phe Pro Trp Cys Gly Leu Leu L
#eu
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:28:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:28:
Trp Leu Met Asp Thr Tyr Val Val Gln Leu L
#eu Arg Ser Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Ser Thr Phe Gln Lys Asn Arg L
#eu Phe Phe Tyr Arg Lys
20
# 25
# 30
Ser Val Trp Ser Lys Leu Gln Ser Ile Gly V
#al Arg Gln His Leu Glu
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:29:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 54 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:29:
Glu Val Arg His His Gln Asp Thr Trp Leu A
#la Met Pro Ile Cys Arg
1 5
# 10
# 15
Leu Arg Phe Ile Pro Lys Pro Asn Gly Leu A
#rg Pro Ile Val Asn Met
20
# 25
# 30
Ser Tyr Ser Met Gly Thr Arg Ala Leu Gly A
#rg Arg Lys Gln Ala Gln
35
# 40
# 45
His Phe Thr Gln Arg Leu
50
(2) INFORMATION FOR SEQ ID NO:30:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:30:
Gln Thr Pro Arg Met Tyr Phe Val Lys Ala A
#sp Val Thr Gly Ala Tyr
1 5
# 10
# 15
Asp Ala Ile Pro Gln Gly Lys Leu Val Glu V
#al Val Ala Asn Met Ile
20
# 25
# 30
Arg His
(2) INFORMATION FOR SEQ ID NO:31:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:31:
Arg Cys Tyr Thr Gln Cys Gln Gly Ile Pro G
#ln Gly Ser Ser Leu Ser
1 5
# 10
# 15
Thr Leu Leu Cys Ser Leu Cys Phe Gly Asp M
#et Glu Asn Lys Leu Phe
20
# 25
# 30
Ala Glu Val
35
(2) INFORMATION FOR SEQ ID NO:32:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:32:
Leu Leu Arg Phe Val Asp Asp Phe Leu Leu V
#al Thr Pro His Leu Asp
1 5
# 10
# 15
Gln
(2) INFORMATION FOR SEQ ID NO:33:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:33:
Ala Lys Thr Phe Leu Ser Thr Leu Val His G
#ly Val Pro Glu Tyr Gly
1 5
# 10
# 15
Cys Met Ile Asn Leu Gln Lys Thr Val Val
20
# 25
(2) INFORMATION FOR SEQ ID NO:34:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:34:
His Cys Leu Phe Pro Trp Cys Gly Leu Leu L
#eu
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:35:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:35:
Trp Ile Phe Glu Asp Leu Val Val Ser Leu I
#le Arg Cys Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Gln Gln Lys Ser Tyr Ser Lys T
#hr Tyr Tyr Tyr Arg Lys
20
# 25
# 30
Asn Ile Trp Asp Val Ile Met Lys Met Ser I
#le Ala Asp Leu Lys Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:36:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:36:
Lys Glu Val Glu Glu Trp Lys Lys Ser Leu G
#ly Phe Ala Pro Gly Lys
1 5
# 10
# 15
Leu Arg Leu Ile Pro Lys Lys Thr Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:37:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:37:
Phe Arg Pro Ile Met Thr Phe Asn Lys Lys I
#le Val Asn Ser Asp Arg
1 5
# 10
# 15
Lys Thr Thr Lys Leu Thr Thr Asn Thr Lys L
#eu Leu Asn
20
# 25
(2) INFORMATION FOR SEQ ID NO:38:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:38:
Gly Gln Pro Lys Leu Phe Phe Ala Thr Met A
#sp Ile Glu Lys Cys Tyr
1 5
# 10
# 15
Asp Ser Val Asn Arg Glu Lys Leu Ser Thr P
#he Leu Lys Thr Thr Lys
20
# 25
# 30
Leu Leu
(2) INFORMATION FOR SEQ ID NO:39:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION:* SEQ ID NO:39:
Lys Phe Tyr Lys Gln Thr Lys Gly Ile Pro G
#ln Gly Leu Cys Val Ser
1 5
# 10
# 15
Ser Ile Leu Ser Ser Phe Tyr Tyr Ala Thr L
#eu Glu Glu Ser Ser Leu
20
# 25
# 30
Gly Phe Leu
35
(2) INFORMATION FOR SEQ ID NO:40:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:40:
Leu Met Arg Leu Thr Asp Asp Tyr Leu Leu I
#le Thr Thr Gln Glu Asn
1 5
# 10
# 15
Asn
(2) INFORMATION FOR SEQ ID NO:41:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:41:
Ala Val Leu Phe Ile Glu Lys Leu Ile Asn V
#al Ser Arg Glu Asn Gly
1 5
# 10
# 15
Phe Lys Phe Asn Met Lys Lys Leu Gln Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:42:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:42:
Gln Asp Tyr Cys Asp Trp Ile Gly Ile Ser I
#le
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:43:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 47 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:43:
Trp Leu Phe Arg Gln Leu Ile Pro Lys Ile I
#le Gln Thr Phe Phe Tyr
1 5
# 10
# 15
Cys Thr Glu Ile Ser Ser Thr Val Thr Ile V
#al Tyr Phe Arg His Asp
20
# 25
# 30
Thr Trp Asn Lys Leu Ile Thr Pro Phe Ile V
#al Glu Tyr Phe Lys
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:44:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:44:
Cys Arg Asn His Asn Ser Tyr Thr Leu Ser A
#sn Phe Asn His Ser Lys
1 5
# 10
# 15
Met Arg Ile Ile Pro Lys Lys Ser Asn Asn
20
# 25
(2) INFORMATION FOR SEQ ID NO:45:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:45:
Phe Arg Ile Ile Ala Ile Pro Cys Arg Gly A
#la Asp Glu Glu Glu Phe
1 5
# 10
# 15
Thr Ile Tyr Lys Glu Asn His Lys Asn Ala I
#le Gln Pro
20
# 25
(2) INFORMATION FOR SEQ ID NO:46:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:46:
Val Leu Pro Glu Leu Tyr Phe Met Lys Phe A
#sp Val Lys Ser Cys Tyr
1 5
# 10
# 15
Asp Ser Ile Pro Arg Met Glu Cys Met Arg I
#le Leu Lys Asp Ala Leu
20
# 25
# 30
Lys Asn
(2) INFORMATION FOR SEQ ID NO:47:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:47:
Lys Cys Tyr Ile Arg Glu Asp Gly Leu Phe G
#ln Gly Ser Ser Leu Ser
1 5
# 10
# 15
Ala Pro Ile Val Asp Leu Val Tyr Asp Asp L
#eu Leu Glu Phe Tyr Ser
20
# 25
# 30
Glu Phe Lys
35
(2) INFORMATION FOR SEQ ID NO:48:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:48:
Ile Leu Lys Leu Ala Asp Asp Phe Leu Ile I
#le Ser Thr Asp Gln Gln
1 5
# 10
# 15
Gln
(2) INFORMATION FOR SEQ ID NO:49:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:49:
Val Ile Asn Ile Lys Lys Leu Ala Met Gly G
#ly Phe Gln Lys Tyr Asn
1 5
# 10
# 15
Ala Lys Ala Asn Arg Asp Lys Ile Leu Ala
20
# 25
(2) INFORMATION FOR SEQ ID NO:50:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:50:
Lys Glu Leu Glu Val Trp Lys His Ser Ser T
#hr
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:51:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 48 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:51:
Trp Leu Tyr Asn Ser Phe Ile Ile Pro Ile L
#eu Gln Ser Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Ser Ser Asp Leu Arg Asn Arg T
#hr Val Tyr Phe Arg Lys
20
# 25
# 30
Asp Ile Trp Lys Leu Leu Cys Arg Pro Phe I
#le Thr Ser Met Lys Met
35
# 40
# 45
(2) INFORMATION FOR SEQ ID NO:52:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 25 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:52:
Asn Asn Val Arg Met Asp Thr Gln Lys Thr T
#hr Leu Pro Pro Ala Val
1 5
# 10
# 15
Ile Arg Leu Leu Pro Lys Lys Asn Thr
20
# 25
(2) INFORMATION FOR SEQ ID NO:53:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 29 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:53:
Phe Arg Leu Ile Thr Asn Leu Arg Lys Arg P
#he Leu Ile Lys Met Gly
1 5
# 10
# 15
Ser Asn Lys Lys Met Leu Val Ser Thr Asn G
#ln Thr Leu
20
# 25
(2) INFORMATION FOR SEQ ID NO:54:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:54:
Phe Gly Arg Lys Lys Tyr Phe Val Arg Ile A
#sp Ile Lys Ser Cys Tyr
1 5
# 10
# 15
Asp Arg Ile Lys Gln Asp Leu Met Phe Arg I
#le Val Lys Lys Lys Leu
20
# 25
# 30
Lys Asp
(2) INFORMATION FOR SEQ ID NO:55:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:55:
Ser Gln Tyr Leu Gln Lys Val Gly Ile Pro G
#ln Gly Ser Ile Leu Ser
1 5
# 10
# 15
Ser Phe Leu Cys His Phe Tyr Met Glu Asp L
#eu Ile Asp Glu Tyr Leu
20
# 25
# 30
Ser Phe Thr
35
(2) INFORMATION FOR SEQ ID NO:56:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:56:
Leu Leu Arg Val Val Asp Asp Phe Leu Phe I
#le Thr Val Asn Lys Lys
1 5
# 10
# 15
Asp
(2) INFORMATION FOR SEQ ID NO:57:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 26 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:57:
Ala Lys Lys Phe Leu Asn Leu Ser Leu Arg G
#ly Phe Glu Lys His Asn
1 5
# 10
# 15
Phe Ser Thr Ser Leu Glu Lys Thr Val Ile
20
# 25
(2) INFORMATION FOR SEQ ID NO:58:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 11 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:58:
Lys Lys Arg Met Pro Phe Phe Gly Phe Ser V
#al
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:59:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:59:
Tyr Tyr Arg Lys
1
(2) INFORMATION FOR SEQ ID NO:60:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:60:
Gly Ile Pro Gln
1
(2) INFORMATION FOR SEQ ID NO:61:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:61:
Asp Asp Phe Leu Leu
1 5
(2) INFORMATION FOR SEQ ID NO:62:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:62:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:63:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe or
#Trp or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:63:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:64:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:64:
Xaa Arg Xaa Xaa Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:65:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 7 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:65:
Xaa Arg Xaa Ile Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:66:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#fron Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:66:
Pro Xaa Xaa Xaa Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:67:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:67:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Xaa Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:68:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Thr or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:68:
Xaa Xaa Xaa Xaa Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:69:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:69:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:70:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Trp or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or His"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:70:
Xaa Xaa Xaa Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:71:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:71:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:72:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:72:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Val Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:73:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:73:
Xaa Arg Xaa Xaa Pro Lys Xaa Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:74:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:74:
Pro Glu Xaa Xaa Phe Xaa Xaa Val Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:75:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:75:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Ile Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:76:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Thr or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:76:
Xaa Xaa Xaa Leu Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:77:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:77:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Arg Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:78:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:78:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:79:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 21
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 25
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:79:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Ile Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:80:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 9
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:80:
Xaa Arg Xaa Xaa Pro Lys Xaa Asn Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:81:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Cys or Ala"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:81:
Pro Arg Xaa Xaa Phe Xaa Xaa Asp Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:82:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 7
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Pro or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ser or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 13
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 16
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 17
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:82:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Ser Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:83:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Leu"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Arg or Lys"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Tyr or Phe"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Ile or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Val"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:83:
Xaa Xaa Xaa Phe Xaa Asp Asp Xaa Leu Xaa X
#aa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:84:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 16 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gly or Val"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 4
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = charged amino acid
selected
#from Asp, Glu, His, Lys or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = polar amino acid
selected
#from Gly, Ser, Thr, Tyr, Cys,
Asn or
#Gln"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Asn or Ser"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:84:
Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Gln Lys Xaa Xaa Xaa
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:85:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:85:
Xaa Xaa Asp Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:86:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 5
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:86:
Xaa Xaa Asp Asp Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:87:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 4 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:87:
Trp Xaa Gly Xaa
1
(2) INFORMATION FOR SEQ ID NO:88:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 6 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:88:
Xaa Leu Gly Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:89:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:89:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:90:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:90:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Tyr
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:91:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 34 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gln or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 28
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 31
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:91:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Trp
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Arg Xaa Xaa
20
# 25
# 30
Xaa Trp
(2) INFORMATION FOR SEQ ID NO:92:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 35 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 2
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 11
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Leu or Ile"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 12
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Gln or Arg"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 29
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 30
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Phe or Tyr"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 32
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = Lys or His"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:92:
Trp Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Phe Phe Trp
1 5
# 10
# 15
Xaa Thr Glu Xaa Xaa Xaa Xaa Xaa Xaa Xaa X
#aa Xaa Xaa Xaa Arg Xaa
20
# 25
# 30
Xaa Xaa Trp
35
(2) INFORMATION FOR SEQ ID NO:93:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:93:
Leu Arg Xaa Xaa Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:94:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 9 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 1
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 3
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:94:
Xaa Arg Xaa Ile Pro Lys Xaa Xaa Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:95:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 5 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:95:
Xaa Arg Xaa Ile Xaa
1 5
(2) INFORMATION FOR SEQ ID NO:96:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:96:
Xaa Xaa Xaa Xaa Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Xaa
(2) INFORMATION FOR SEQ ID NO:97:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 17 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 6
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 8
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 10
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:97:
Pro Xaa Leu Tyr Phe Xaa Xaa Xaa Asp Xaa X
#aa Xaa Xaa Tyr Asp Xaa
1 5
# 10
# 15
Ile
(2) INFORMATION FOR SEQ ID NO:98:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 22 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:98:
Tyr Xaa Xaa Xaa Xaa Gly Xaa Xaa Gln Gly X
#aa Xaa Xaa Ser Xaa Xaa
1 5
# 10
# 15
Xaa Xaa Xaa Xaa Xaa Xaa
20
(2) INFORMATION FOR SEQ ID NO:99:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 15 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(ix) FEATURE:
(A) NAME/KEY: Modified-si
#te
(B) LOCATION: 14
(D) OTHER INFORMATION:
#/product= "OTHER"
/note=
#"Xaa = hydrophobic amino acid
selected
#from Ala, Leu, Ile, Val, Pro,
Phe, Trp
# or Met"
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:99:
Gln Xaa Xaa Gly Ile Pro Gln Gly Ser Xaa L
#eu Ser Xaa Xaa Leu
1 5
# 10
# 15
(2) INFORMATION FOR SEQ ID NO:100:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 13 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:100
#:
Xaa Xaa Xaa Xaa Xaa Xaa Asp Asp Xaa Leu X
#aa Xaa Xaa
1 5
# 10
(2) INFORMATION FOR SEQ ID NO:101:
(i) SEQUENCE CHARACTERISTICS:
(A) LENGTH: 12 amino
#acids
(B) TYPE: amino acid
(C) STRANDEDNESS:
(D) TOPOLOGY: linear
(ii) MOLECULE TYPE: peptide
(xi) SEQUENCE DESCRIPTION: SEQ ID NO:101
#:
Leu Leu Arg Phe Xaa Asp Asp Phe Leu Leu X
#aa Thr
1 5
# 10
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