Molecular interactions and regulatory events of telomere proteins

项目摘要/摘要 所有的遗传信息都存储在DNA中，DNA被蛋白质错综复杂地包裹起来，形成染色体。 端粒是一种核蛋白复合体，它覆盖并保护染色体末端，以防止它们 磨损，融合在一起，有辱人格。除了覆盖和保护染色体末端外， 端粒调节端粒酶的招募，端粒酶是一种专门的酶，合成端粒DNA以 与复制聚合酶协作，确保完整的染色体复制。在过去的四年里， 在被诊断为一系列疾病的患者中发现了端粒末端结合蛋白的多个点突变 疾病，包括许多不同类型的癌症。这些观察结果表明， 端粒蛋白的结构和/或功能导致基因组不稳定。POT1(端粒保护 1)是与人类疾病相关的突变最多的端粒蛋白。POT1形成异二聚体络合物 与另一种端粒末端结合蛋白TPP1一起执行不同但同样关键的功能。具体来说， POT1-TPP1与端粒末端3‘端结合，帮助端粒募集端粒酶并调节端粒活性 端粒酶介导的端粒合成。此外，POT1-TPP1蛋白保护端粒DNA不被 由DNA损伤机器识别和修复。最后，POT1-TPP1杂二聚体表现出非凡的性能 序列特异性，区分与非端粒序列的RNA或DNA的结合。 本研究的目的是研究POT1-TPP1在端粒中的多种不同作用 维修。我们将结合结构-功能研究来确定决定 POT1-TPP1发挥功能，我们将用细胞结果来证实机制研究。我们将介绍 POT1和TPP1的几个与疾病相关的点突变和蛋白变化的特征 结构，以及蛋白质与蛋白质和蛋白质与核酸的相互作用。这次调查的结果将是 揭示由致病突变引起的结构和功能变化，并将用于更好地 了解天然异二聚体的不同功能。这项研究中所做的工作将有助于 染色体末端保护调节染色体末端保护的基本组装、组织和功能运动

PROJECT SUMMARY/ABSTRACT All genetic information is stored in DNA that is intricately wrapped by proteins to form chromosomes. Telomeres are the nucleoprotein complexes that cap and protect the ends of chromosomes to prevent them from fraying, fusing together, and degrading. In addition to capping and protecting the ends of chromosomes, telomeres regulate the recruitment of telomerase, a specialized enzyme that synthesizes telomere DNA to collaborate with replicative polymerases and ensure complete chromosome replication. Over the past four years, multiple point-mutations have been identified in telomere end-binding proteins in patients diagnosed with a range of disorders, including many different types of cancer. These observations indicate that subtle changes in the structure and/or function of telomere proteins contributes to genome instability. POT1 (Protection of Telomeres 1) is the most mutated telomere protein associated with human disorders. POT1 forms a heterodimeric complex with another telomere end-binding protein, TPP1, to perform diverse but equally critical functions. Specifically, POT1-TPP1 binds to the extreme 3’ end of telomeres and helps recruit telomerase to the telomere and regulates telomerase-mediated telomere synthesis. In addition, the POT1-TPP1 proteins shield telomere DNA from being recognized and repaired by DNA damage machinery. Finally, the POT1-TPP1 heterodimer exhibits extraordinary sequence specificity that provides discrimination against binding to RNA or to DNA with non-telomere sequence. The objective of the present proposal is to investigate the multiple and diverse roles of POT1-TPP1 in telomere maintenance. We will combine structure-function studies to determine the molecular interactions that dictate POT1-TPP1 functions and we will corroborate the mechanistic studies with cellular outcome. We will introduce several disease-associated point mutations to both POT1 and TPP1 and characterize alterations in protein structure, as well as protein-protein and protein-nucleic acid interactions. The results from this investigation will reveal both structural and functional alterations introduced by pathogenic mutations and will be used to better understand the diverse functions of the native heterodimer. The work performed in this study will shed light on the fundamental assembly, organization, and functional motions that regulate chromosome end protection.