Mechanisms and Evolution of the Telomere Protective Complex Cdc13-Stn1-Ten1

智力优势：端粒是位于真核生物线性染色体末端的特殊结构。这些结构由重复的DNA序列和一组复杂的蛋白质组成，这些蛋白质覆盖着染色体末端，保护染色体免受有害重排的影响。本研究的总体目标是研究CDC13-Stn1-Ten1(CST)蛋白复合体的机制，它构成了端粒的一个关键的和广泛保守的成分。尽管进行了大量的分析，但目前对这种复合体是如何组合在一起以及它如何保护端粒DNA的理解存在许多空白。初步研究揭示了CST复合体的两个意想不到的特征：它是二聚体，比其他亚基含有更多的Stn1拷贝。此外，在许多假丝酵母菌中发现了第二个调节端粒的类似CDC13的蛋白(称为CDC13B)。通过分析CST组分之间以及CST和端粒DNA之间的详细相互作用，这项研究将为细胞如何维持染色体稳定性提供关键的见解。此外，通过研究CDC13和CDC13B之间的功能重叠或多样化，本研究将扩大目前对端粒进化的理解。这些发现也可能影响其他组织的端粒研究。广泛影响：该项目包括在纽约城市大学(CUNY)下属的Hostos社区学院(HCC)对未被充分代表的少数族裔本科生进行培训和发展。有动力的学生将在他们的母校接受特别定制的实验室课程的初步培训。然后，他们将在暑期实习期间直接参与该项目。由于实验子集的协议性质良好，学生将有现实的机会为该项目做出有意义的贡献。学生们的成就将在HCC和其他论坛上展示。由学生撰写的科学报告将发表在在线杂志《霍斯托斯学生研究杂志》上。他们还将在年度少数民族学生生物医学研究会议(ABRCMS)上发表。这些活动应该会引起哈佛大学同龄人和其他人的兴趣，并有助于激励和鼓励这些学生追求科学事业。此外，虽然该项目主要关注端粒生物学，但这些发现也将提供对蛋白质-核酸相互作用以及蛋白质及其DNA靶标的共同进化的一般见解。

Intellectual merit: Telomeres are specialized structures located at the ends of linear eukaryotic chromosomes. These structures consist of repetitive DNA sequences and a complex array of proteins that cap chromosome ends and protect chromosomes from deleterious rearrangements. The overall goal of this research is to investigate the mechanisms of the Cdc13-Stn1-Ten1 (CST) protein complex, which constitutes a critical and widely conserved component of telomeres. Despite a great deal of analysis, there are numerous gaps in the current understanding of how this complex is put together and how it protects telomere DNA. Preliminary studies uncovered two unexpected features of the CST complex: it is dimeric and contains more copies of Stn1 than the other subunits. Moreover, a second Cdc13-like protein (called Cdc13B) that regulates telomeres was identified in many Candida species. By analyzing the detailed interactions among the CST components and those between CST and telomeric DNA, this research will provide critical insights on how the cells maintain chromosome stability. In addition, by studying the functional overlap or diversification between Cdc13 and Cdc13B, this investigation will expand current understanding of the evolution of telomeres. The findings are also likely to influence telomere research in other organisms.Broader impact: This project includes the training and development of underrepresented minority undergraduates at Hostos Community College (HCC), part of the City University of New York (CUNY). Motivated students will receive initial training at their home institution in a specially tailored laboratory course. They will then directly participate in the project during summer internships. Due to the well-established nature of the protocols for subsets of the experiments, the students will have realistic opportunities for making meaningful contributions to the project. The students' achievements will be showcased at HCC and other forums. Scientific reports authored by students will be published in the HCC on-line journal Hostos Journal of Student Research. They will also be presented at the Annual Biomedical Research Conference for Minority Students (ABRCMS). These activities should generate interest among peers at HCC and beyond, and help motivate and encourage these students to pursue careers in science. Moreover, while the project has a primary focus on telomere biology, the findings will also provide general insights on protein-nucleic acid interactions as well as on the co-evolution of proteins and their DNA-targets.