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Regulation of Telomere Maintenance in Fission Yeast

裂殖酵母端粒维持的调控

基本信息

批准号：
9269576
负责人：
Toru Nakamura
金额：
$ 36.19万
依托单位：
UNIVERSITY OF ILLINOIS AT CHICAGO
依托单位国家：
美国
项目类别：
财政年份：
2006
资助国家：
美国
起止时间：
2006-08-01 至 2020-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/9269576
关键词：
Affect Aging Animal Model Aplastic Anemia Binding Binding Sites C-terminal Cell Proliferation Cells Chromosomes Collaborations Complex DNA DNA Damage DNA Repair DNA damage checkpoint DNA polymerase A DNA-Directed DNA Polymerase Data Disease Dissociation Dyskeratosis Congenita Ensure Eukaryotic Cell Failure Fission Yeast Functional disorder Funding Future Genetic Recombination Genome Genome Stability Genomic Instability Goals Hamman-Rich syndrome Health Human Inherited Knowledge Laboratories Lead Lysine Maintenance Mammalian Cell Mass Spectrum Analysis Modeling Mutation Nucleoproteins Organism Pattern Phosphorylation Phosphorylation Site Phosphotransferases Play Post-Translational Protein Processing Prevention Proteins Recruitment Activity Regulation Research Research Project Grants Role Serine Single-Stranded DNA Structure Syndrome Tail Telomerase Telomere Maintenance Threonine Time Tissues age related base chromosome fusion ds-DNA effective therapy experimental study genetic analysis genome integrity human disease insight interest neoplastic cell prevent public health relevance response telomere treatment strategy tumor tumor growth

项目摘要

DESCRIPTION (provided by applicant): Our laboratory is interested in understanding how eukaryotic cells ensure the maintenance of telomeres, the natural ends of linear eukaryotic chromosomes. Evolutionarily conserved shelterin and CST (CTC1/Cdc13- STN1-TEN1) complexes play essential roles in telomerase recruitment and protection of telomeres against DNA repair and checkpoint factors. Stable maintenance of telomeres is critical to preserve genomic integrity and prevent accumulation of undesired mutations that might lead to tumor formation. Regulation of telomere structures and telomerase also affect cell proliferation and tissue maintenance in aging organisms. Therefore, basic mechanistic studies investigating how telomere and DNA damage response proteins collaborate in proper telomere maintenance should provide critical insights necessary to help devise more effective treatment strategies against tumors or other age related diseases. Our proposed research projects utilize fission yeast Schizosaccharomyces pombe. Fission yeast telomeres serve as a good model for human telomeres, since proteins involved in telomere maintenance are highly conserved between fission yeast and humans. In addition, the ability of fission yeast cells to survive severe telomer dysfunction by circularizing all their chromosomes provides unique opportunities to study functional contributions of essential telomere maintenance factors, without being hindered by cell lethality. During the past funding period, we identified phosphorylation of the shelterin subunit Ccq1 at Threonine-93 (Thr93) by DNA damage checkpoint kinases Rad3ATR and Tel1ATM as the critical post-translational modification that promotes interaction between Ccq1 and the telomerase regulatory subunit Est1 to allow telomerase recruitment. Furthermore, we demonstrated that fission yeast shelterin and Stn1-Ten1 complexes interact, and that SUMOylation of the shelterin subunit Tpz1TPP1 at Lysine-242 (Lys242) facilitates shelterin-Stn1-Ten1 interaction to allow efficient accumulation of Stn1-Ten1 at telomeres and to limit telomerase-dependent telomere elongation. Our detailed analyses of temporal binding patterns for DNA polymerases, telomerase, shelterin and Stn1 also demonstrated that Rap1, Poz1 and Stn1-Ten1 promote timely dissociation of telomerase from telomeres by promoting timely recruitment of Polα to complete lagging strand synthesis at telomeres. We have also successfully identified numerous phosphorylation sites on Tpz1TPP1 and Ccq1 by mass spectrometry. For the upcoming funding period, we propose experiments to define the functional significance of additional phosphorylation sites in Tpz1 and Ccq1 (Aims1-2) and investigate how shelterin, Stn1-Ten1 and Polα collaborate to ensure telomere maintenance (Aim3). Since TPP1 is also highly phosphorylated and CST- and shelterin- dependent coordination of lagging strand synthesis and telomerase recruitment also play critical roles in telomere maintenance in mammalian cells, successful completion of the proposed experiments will likely have major impacts on future mammalian telomere studies.