Eukaryotic Telomere Dynamics

真核端粒动力学

• 批准号: 6823434
• 负责人: Arthur J. Lustig
• 金额: $ 27.18万
• 依托单位: TULANE UNIVERSITY OF LOUISIANA
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-07-01 至 2008-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6823434
• 关键词: Saccharomyces cerevisiae; aging; alleles; cell cycle; chromosome deletion; cytotoxicity; eukaryote; meiosis; phosphorylation; protein structure function; recombinant proteins; telomerase; telomere

DESCRIPTION (provided by applicant): Telomeres, the specialized protein-DNA structures present at the chromosomal terminus serve as 'caps' to prevent deleterious processes that would result in toss of linear chromosomes. The maintenance of an appropriate length of telomeric simple sequences to provide cap function is therefore essential for cell viability. Indeed, defects in telomere size control have been linked with both aging and oncogenesis. We have been studying the mechanism of size control in the yeast Saccharomyces cerevisiae as a model system. The basic outline of telomere size control is remarkably similar in yeast and vertebrates. Hence, the construction of a model system that can be easily manipulated gives us the opportunity to provide the framework for higher eukaryotic functional homologs. Previous studies have uncovered a process termed telomeric rapid deletion (TRD) that excises over-elongated telomere tracts to wild type sizes by a recombination mechanism. Two components regulate this process: the mechanism for the deletion process, and the mechanism of sizing among telomeres that governs the precision of deletion. The major goal in this proposal is to understand the mechanism of TRD. Three aims will be pursued. The first aim is the characterization of the cell cycle control of TRD and the characterization of meiotic TRD which displays dramatically increased rates of TRD. The only protein known to be essential for TRD is the recombination protein Mre11. The second aim is to study the essential role of Mre11 in TRD through the extensive characterization of a battery of mis-sense alleles falling within unique domains of the protein The third aim examines an unusual allele of Mre11, A470T, that confers two major phenotypes, a loss of TRD precision and an ability to bypass senescence conferred by a loss of telomerase. Specific hypotheses f or the function of Mre11 in checkpoint control on telomere processing are tested using the tools made available from preliminary data. Proteins that interact with the motif surrounding A470T will be sought through the use of the Tap-tag method of isolating soluble native complexes.

描述（由申请人提供）：端粒，染色体末端上存在的专门蛋白-DNA结构用作“帽”，以防止有害过程，从而导致线性染色体抛弃。因此，维持适当的端粒简单序列以提供CAP功能对于细胞活力至关重要。实际上，端粒尺寸控制的缺陷已与衰老和肿瘤发生有关。我们一直在研究酿酒酵母作为模型系统中尺寸控制的机理。在酵母和脊椎动物中，端粒尺寸控制的基本轮廓非常相似。因此，可以轻松操纵的模型系统的构建使我们有机会为更高的真核功能同源物提供框架。先前的研究发现了一种称为端粒快速删除（TRD）的过程，该过程通过重组机制将过度延长的端粒型量化为野生型尺寸。两个组件调节了此过程：缺失过程的机制，以及控制缺失精度的端粒之间的大小机制。该提案的主要目标是了解TRD的机制。将追求三个目标。第一个目的是对TRD的细胞周期控制的表征以及减数分裂TRD的表征，它显示出TRD的速率急剧提高。唯一已知在TRD所必需的蛋白质是重组蛋白MRE11。第二个目的是通过广泛表征属于蛋白质独特域内的一系列错误 - 敏感等位基因的广泛特征来研究MRE11在TRD中的基本作用。第三个目标研究了MRE11（A470T）的异常等位基因，这些等位基因赋予了两个主要的表型，这是TRD精确性的损失和通过Telmasese of telomasase of telemasese of telemasese of Telmasese的能力。使用初步数据可用的工具测试了端粒处理检查点控制点中的特定假设或MRE11的功能。通过使用TAP-TAG方法隔离可溶性天然复合物的方法，将寻求与A470T周围基序相互作用的蛋白质。