Chemistry: molecular biology and microbiology – Animal cell – per se ; composition thereof; process of... – Method of regulating cell metabolism or physiology
Reexamination Certificate
1999-04-06
2001-10-09
Brusca, John S. (Department: 1635)
Chemistry: molecular biology and microbiology
Animal cell, per se ; composition thereof; process of...
Method of regulating cell metabolism or physiology
C435S091100, C435S069100, C435S320100, C435S325000, C536S023100, C536S023500, C530S350000, C530S387100
Reexamination Certificate
active
06300131
ABSTRACT:
TECHNICAL FIELD
The invention relates to a human staufen polypeptide that is associated with telomerase.
BACKGROUND OF THE INVENTION
Telomerase is a specialized ribonucleoprotein (RNP) reverse transcriptase that is essential for telomere maintenance. Telomerase uses an internal RNA template to synthesize telomeric repeat sequences onto chromosome ends. Deletion of the essential RNA component of telomerase leads to progressive telomere shortening, chromosome instability and cell death in both yeast and mouse cells. This multi-subunit enzyme is regulated at several levels in human cells.
The telomerase enzyme is made up of an essential core as well as several accessory proteins. The core telomerase consists of the RNA component (Telomerase RNA, TR) and the catalytic subunit (Telomerase Reverse Transcriptase, TERT). The structure of the RNA component is conserved in ciliates, in which the RNA is 150-200 nucleotides (nt) in length. In mammalian cells, the RNA component is significantly larger, 390-450 nt. Feng, J. et al.,
Science,
1995, 269:1236-1241. The catalytic TERT component, first identified in the ciliate Euplotes, has homologues in yeast (EST 2), human (hTERT), and mouse (mTERT). TERT contains sequence motifs similar to reverse transcriptase and mutations of essential aspartate residues that are conserved in the catalytic triad of reverse transcriptases eliminates telomerase activity. Minimal telomerase activity can be reconstituted in an in vitro transcription/translation extract using TERT and TR components, indicating that these are sufficient for catalysis. Weinrich, S. L. et al.,
Nat. Genet.,
1997, 17:498-502.
Both telomere length and telomerase activity have been implicated in cellular senescence and cancer. In most somatic cells, telomerase activity is not detected and telomeres shorten with each division. Allsopp, R. C. et al.,
Proc. Natl. Acad. Sci. USA,
1992, 89:1014-1018. Artificial elongation of telomeres by ectopic hTERT expression in primary human cells leads to telomere elongation and a bypass of cellular senescence, suggesting that telomere shortening may trigger cellular senescence in primary human cells. During immortalization of mammalian cells in culture, telomerase is activated, telomere length is stabilized, and cells continue to proliferate, suggesting that telomerase activation and telomere stabilization are required for the long term growth of cancer cells. Telomerase activity is present in the vast majority of human tumors while little activity is found in the normal tissues from which the tumors were derived. Together, these data lead to the proposal that telomerase inhibition may inhibit tumor growth. See, for example, Harley, C. B. et al.,
Cold Spring Harbor Symp. Quant. Biol.,
1994, 59:307-315.
New evidence also indicates that telomerase plays a role in tumor initiation, not just in long term tumor growth. Telomerase null mice with significantly shortened telomeres show an increased rate of tumor formation with age compared with wild-type mice, suggesting loss of telomere function leads to increased genetic instability. Furthermore, in cells lacking the p53 gene, absence of telomerase increased the rate of focus formation after transfection of myc and RAS. This suggests that the absence of both telomerase and p53 cooperated to increase genetic instability that leads to tumor initiation. Thus, characterization of telomerase and its associated components is important to understanding tumor formation.
SUMMARY OF THE INVENTION
The invention is based on the identification of telomerase-associated proteins that bind telomerase RNA and that may play a role in telomerase assembly, transport, and regulation. As described herein, human staufen (hStau) polypeptide and ribosomal associated protein L22 bind human telomerase RNA and are associated with telomerase activity in vivo.
In one aspect, the invention features an isolated human staufen polypeptide, wherein the polypeptide includes an amino acid sequence substantially identical to the amino acid sequence of about residue 49 to about residue 496 of SEQ ID NO:2. For example, the polypeptide can be substantially identical to the amino acid sequence of SEQ ID NO:2. The polypeptide also can be, for example, the amino acid sequence of SEQ ID NO:2 or the amino acid sequence of about residue 49 to about residue 496 of SEQ ID NO:2. Polypeptides that include the amino acid sequence of SEQ ID NO:2 can have a molecular weight of approximately 55 kDa. Polypeptides of the invention bind RNA. For example, the polypeptide can bind double-stranded RNAs such as telomerase RNA. The polypeptide can be in a complex with the catalytic subunit of telomerase.
The invention also features an isolated polynucleotide encoding a human staufen polypeptide. The encoded polypeptide can include an amino acid sequence substantially identical to the amino acid sequence of about residue 49 to about residue 496 of SEQ ID NO:2. For example, the polypeptide can include the amino acid sequence of SEQ ID NO:2. The polynucleotide can have a nucleotide sequence at least 70%, 80%, 90%, or 95% identical to the nucleotide sequence of SEQ ID NO:1.
Polynucleotides of the invention also can be at least 150 nucleotides in length and hybridize under stringent conditions to the nucleotide sequence of SEQ ID NO:1 or the complement thereof. For example, the polynucleotide can include the nucleotide sequence of SEQ ID NO:1.
In another aspect, the invention features an antibody having specific binding affinity for a human staufen polypeptide that includes, for example, the amino acid sequence of SEQ ID NO:2. The antibody can be polyclonal or monoclonal.
The invention also features a method for inhibiting telomerase activity. The method includes administering to a cell an amount of an agent effective to inhibit the interaction between a telomerase-associated polypeptide and telomerase. The telomerase-associated polypeptide can be, for example, human staufen polypeptide or ribosomal associated protein L22.
Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used to practice the invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated by reference in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods, and examples are illustrative only and not intended to be limiting.
Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
REFERENCES:
Wickham et al., “Mammalian Staufen is a Double-stranded RNA and Tubulin Binding Protein which Localizes to the Rough Endoplasmic Reticulum”, Molecular and Cellular Biology, pp. 2220-2230, Mar. 1999.*
Berendsen, “A Glimpse of the Holy Grail?”, Science, vol. 282, pp. 642-643, Mar. 1999.*
Branch TIBS 23, 1998, pp. 45-50.*
Crooke “Antisense Research & Applications” pp. 1-50, 1998.*
Adams et al., “3,400 new expressed sequence tags identify diversity of transcripts in human brain”,Nature Genetics, 4:256-267.
Genbank Accession No. 317397, Adams, MD., May 25, 1993.
Desgroseillers, L., et al., Localization of a Human Double-Stranded RNA-binding protein Gene (STAU) to Band 20q13.1 by Fluorescence in Situ Hybridization Genomics, 1996, Genomics, 36, 3: pp. 527-529.
Ferrandon, D., et al., RNA-RNA Interaction is Required for the Formation of Specific Bicoid-mRNA 3′ UTR-STAUFEN Ribonucleo-protein Particles, 1997, The EMBO Journal, 16, 7: PP. 1751-1758.
Greider Carol W.
Le Siyuan
Brusca John S.
Fish & Richardson P.C.
Johns Hopkins University
Lacourciere Karen A
LandOfFree
Telomerase-associated proteins does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Telomerase-associated proteins, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Telomerase-associated proteins will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2557044