Telomerase is a ribonucleoprotein complex responsible for extending the dG-rich strand of the telomere terminal repeats. It employs a small segment of a stably associated RNA component as template, and pre-existing chromosomal ends as primers to accomplish reverse transcription. Telomerase activity is specifically activated in cancer cells, and promotes neoplastic transformation by conferring cells with unlimited replicative potentials. Specific inactivation of telomerase in tumor cells leads to telomere shortening and apoptosis, validating the potential of telomerase inhibitors in anti-cancer therapy. The long-term objective of this research plan is to establish a detailed molecular understanding of telomerase structure, mechanism, assembly and regulation. This proposal focuses on a key component of the telomerase complex, the reverse transcriptase polypeptide (known as TERT). Located within the C-terminal half of this protein are essential reverse-transcriptase-like motifs that participate in polymerization. Comparative sequence analysis by others and the principal investigator revealed in the N-terminal half of the protein four novel conserved motifs (named GQ, CP, QFP, and T based primarily on key invariant residues within each motif) that are likely to be critical to its function. The principal investigator hypothesizes that these motifs mediate crucial activities of TERT, such as RNA-binding, protein stability, complex assembly, interaction with regulatory factors, and reverse transcription. The goals of this proposal are directed toward elucidating the precise molecular functions of all four motifs. The methodology involves biochemical and genetic analysis of telomerase complex bearing deletion and substitution mutations, as well as biophysical and structural characterization of critical protein domains in isolation. Given the wealth of available biochemical and genetic tools, the budding yeast Saccharomyces cerevisiae represents an ideal model system for undertaking such an endeavor. Furthermore, because of the conserved nature of the motifs being analyzed, the findings should provide general insights on telomerase structure and mechanisms.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM062631-05
Application #
6874543
Study Section
Biochemistry Study Section (BIO)
Program Officer
Jones, Warren
Project Start
2001-04-01
Project End
2007-03-31
Budget Start
2005-04-01
Budget End
2007-03-31
Support Year
5
Fiscal Year
2005
Total Cost
$254,250
Indirect Cost
Name
Weill Medical College of Cornell University
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
060217502
City
New York
State
NY
Country
United States
Zip Code
10065
Yu, Eun Young; Kojic, Milorad; Holloman, William K et al. (2013) Brh2 and Rad51 promote telomere maintenance in Ustilago maydis, a new model system of DNA repair proteins at telomeres. DNA Repair (Amst) 12:472-9
Lue, Neal F; Zhou, Ruobo; Chico, Lidia et al. (2013) The telomere capping complex CST has an unusual stoichiometry, makes multipartite interaction with G-Tails, and unfolds higher-order G-tail structures. PLoS Genet 9:e1003145
Lue, Neal F; Chan, Jamie (2013) Duplication and functional specialization of the telomere-capping protein Cdc13 in Candida species. J Biol Chem 288:29115-23
Lue, Neal F; Yu, Eun Young; Lei, Ming (2013) A popular engagement at the ends. Nat Struct Mol Biol 20:10-2
Hsu, Min; Yu, Eun Young; Sprusansky, Ondrej et al. (2012) Functional analysis of the single Est1/Ebs1 homologue in Kluyveromyces lactis reveals roles in both telomere maintenance and rapamycin resistance. Eukaryot Cell 11:932-42
Sun, Jia; Yang, Yuting; Wan, Ke et al. (2011) Structural bases of dimerization of yeast telomere protein Cdc13 and its interaction with the catalytic subunit of DNA polymerase ?. Cell Res 21:258-74
Belfort, Marlene; Curcio, M Joan; Lue, Neal F (2011) Telomerase and retrotransposons: reverse transcriptases that shaped genomes. Proc Natl Acad Sci U S A 108:20304-10
Lue, Neal F; Hsu, Min (2011) A web of interactions at the ends. Mol Cell 42:269-71
Lue, Neal F (2010) Plasticity of telomere maintenance mechanisms in yeast. Trends Biochem Sci 35:8-17
Lue, Neal F; Li, Zhaohui (2007) Modeling and structure function analysis of the putative anchor site of yeast telomerase. Nucleic Acids Res 35:5213-22

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