Regulation of Telomere Length

端粒长度的调节

基本信息

批准号：
7149122
负责人：
Kurt W Runge
金额：
$ 28.29万
依托单位：
CLEVELAND CLINIC LERNER COM-CWRU
依托单位国家：
美国
项目类别：
财政年份：
1994
资助国家：
美国
起止时间：
1994-05-01 至 2009-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7149122
关键词：
Affect Amino Acids Binding Biological Assay Biological Models Bypass Cell Aging Cell Cycle Cell Death Cells Chromatin Structure Chromosomal Breaks Chromosomes Complex Count DNA DNA Damage DNA Sequence DNA Sequence Rearrangement DNA biosynthesis DNA damage checkpoint DNA-Binding Proteins Data Equilibrium Eukaryota Eukaryotic Cell Facility Construction Funding Category Genetic Recombination Germ Cells Goals Human Interphase Cell Length Measures Meclp Metric Modeling Mutation Nucleoproteins Numbers Pathway interactions Phase Process Protein Binding Proteins Recruitment Activity Regulation Research Personnel Role Running Somatic Cell Staging Structure System Telomerase Telomere Shortening Telomere-Binding Proteins Testing Time Work Yeasts base chromatin immunoprecipitation chromosome replication genetic regulatory protein in vivo mutant paralogous gene prevent programs protein activation research study response senescence telomere tumorigenic

项目摘要

Telomeres are the nucleoprotein complexes that allow the complete replication of chromosome ends and distinguish these ends from double-strand breaks. Telomere DNA consists of tandem arrays of TG-rich repeats. The length of these repeat tracts is kept nearly constant in human germ cells and yeast by regulating the processes of lengthening, via telomerase, and shortening, due to incomplete replication or nucleolytic degradation. How these two processes are regulated to give a constant telomere length is unknown. In human somatic cells, the length of the repeats decreases as cells divide, leading to cell senescence when telomeres become too short. How telomere length information is transmitted to the cell cycle machinery is unknown. Our long-term goal is to use yeast as a model system to understand these processes. Yeast measure telomere length by counting the number of molecules of the major telomere binding protein Raplp; however, how Raplp molecules are counted is under debate. We developed a model for telomere length regulation based on our construction of yeast synthetic telomeres. We propose that yeast telomeres form a folded structure with Raplp and 2 regulatory proteins, Riflp and Rif2p, to count Raplp molecules and block elongation. Short telomeres have too few Raplp molecules to form this structure, so they are elongated. Other models suggest that Sir proteins also regulate length, and we have devised assays to directly test this possibility. Tel2p binds to telomeres in vivo and regulates their length. Tel2p mutants alter telomere length and the cellular response to a single double-strand break and other forms of DNA damage. We hypothesize that Tel2p binds to telomeres and double-strand breaks to regulate activation of DNA damage checkpoints. The activities of the checkpoint proteins Tellp and Meclp suggest that they are involved in these processes. Our specific aims are to determine 1) the protein composition of the structure that regulates telomere length; 2) if Tellp and Meclp are recruited to telomeres of different lengths; and 3) how Tel2p alters telomere length and the cellular response to DNA damage and if Tel2p acts at double-strand breaks in vivo.

端粒是核蛋白复合物，允许染色体末端的完全复制，并将这些末端与双链断裂区分开。端粒DNA由富含TG的重复序列组成。由于不完全的复制或核解溶解降解，通过调节延长，通过端粒酶和缩短的过程，这些重复区的长度在人类生殖细胞和酵母中保持恒定。如何调节这两个过程以给出恒定的端粒长度。在人类体细胞中，重复的长度随着细胞的分裂而减小，当端粒变得太短时会导致细胞衰老。端粒长度信息如何传输到细胞周期机械尚不清楚。我们的长期目标是将酵母作为模型系统来了解这些过程。酵母通过计算主要端粒结合蛋白RAPLP的分子数来测量端粒长度；但是，如何计算RAPLP分子正在争论中。我们根据酵母合成端粒的构建开发了用于端粒长度调节的模型。我们建议酵母端粒形成一种折叠结构，其中Raplp和2种调节蛋白RIFLP和RIF2P，以计算RAPLP分子和阻断延伸。短端粒具有太少的Raplp分子，无法形成这种结构，因此它们被拉长了。其他模型表明，SIR蛋白质也调节长度，我们已经设计了测定法以直接测试这种可能性。 Tel2P在体内与端粒结合并调节其长度。 Tel2P突变体改变了端粒长度，并对单个双链断裂和其他形式的DNA损伤的细胞反应。我们假设TEL2P与端粒结合和双链断裂，以调节DNA损伤检查点的激活。检查点蛋白Tellp和MECLP的活动表明它们参与了这些过程。我们的具体目的是确定1）调节端粒长度的结构的蛋白质组成； 2）如果将TellP和MECLP招募到不同长度的端粒； 3）TEL2P如何改变端粒长度和对DNA损伤的细胞反应以及Tel2P在体内的双链断裂中的作用。