Meiotic Centromere Behavior in Yeast

酵母减数分裂着丝粒行为

• 批准号: 8294613
• 负责人: DEAN S DAWSON
• 金额: $ 28.87万
• 依托单位: OKLAHOMA MEDICAL RESEARCH FOUNDATION
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-05 至 2014-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8294613
• 关键词: Affinity Chromatography; Behavior; Biological Assay; Cells; Centromere; Chromosome Arm; Chromosome Pairing; Chromosome Segregation; Chromosomes; Complex; Congenital Abnormality; DNA; DNA Double Strand Break; DNA biosynthesis; Drosophila genus; Female; Generations; Genetic Recombination; Germ Cells; Heterochromatin; Homologous Gene; Kinetochores; Laboratory Organism; Lead; Light; Literature; Mediating; Meiosis; Meiotic Recombination; Metaphase; Methods; Microtubules; Mus; Onions; Organism; Phase; Process; Prophase; Proteins; Proteomics; Publishing; Regulation; Reporting; Role; Saccharomycetales; Signal Transduction; Sister Chromatid; Staging; Synaptonemal Complex; Testing; Time; Wheat; Yeasts; chromosome movement; member; prevent; protein purification; public health relevance; research study; segregation

DESCRIPTION (provided by applicant): Over the past thirty years there have been sporadic reports in the literature of pairing between the centromeres of both homologous and non-homologous chromosomes at two different stages of meiosis. First, studies in a variety of organisms (onions, wheat, budding yeast, mice) have revealed that early in meiosis, just after DNA replication, centromeres arrange themselves in pairs. This pairing is primarily between non-homologous centromeres. This non-homologous, early, meiotic centromere pairing dissolves as homologous chromosomes become aligned in later meiotic prophase. Second, centromeres can also actively pair at a later stage of meiosis. For example, studies with budding yeast and female Drosophila have shown that partner chromosomes that have failed to recombine (non-exchange chromosomes) pair at their centromeres (or pericentric heterochromatin) in late prophase, when homologous chromosomes are completely synapsed. This late meiotic centromere pairing between non-exchange partners promotes their disjunction at the first meiotic division. In budding yeast, both the early and late stages of centromere pairing depend upon the synaptonemal complex (SC) protein, Zip1. This project aims to characterize the two phases of centromere pairing in meiosis, test whether they are mechanistically related, or distinct, and determine how they impact the segregation of chromosomes in meiosis I. Because observations of meiotic centromere pairing have been gathered from such a diverse range of experimental organisms, the proposed experiments may reveal the details of a conserved, but largely unrecognized, aspect of meiotic chromosome behavior. The project is organized into five groups of experiments. The first group of experiments determines the region of Zip1 that is involved in association with the centromere in early meiosis and uses affinity purification methods to identify proteins that are involved in the early phase of centromere pairing. Little is known about the transition from early to later centromere pairing. A second group of experiments will explore this transition and shed light on the relationship of the two stages. What is the purpose of aligning non-homologous centromeres at the beginning of a process (meiosis I) that is ultimately intended to pair then separate homologous chromosomes? A third group of experiments tests the hypothesis that non-homologous centromere pairing blocks the formation of crossovers near to centromeres. Such crossovers are known to disrupt meiosis I chromosome segregation fidelity in many organisms. The final two groups of experiments will explore first, how Zip1 promotes the pairing of centromeres in later meiotic prophase, and second, will test the hypothesis that this late centromere pairing promotes the attachment of centromeres to opposite poles of the meiosis I spindle, and in doing so, contributing to meiosis I segregation fidelity in important ways. PUBLIC HEALTH RELEVANCE: Errors in the process of distributing chromosomes to the gametes is the major cause of birth defects. This project uses budding yeast to identify undiscovered ways in which a component of the chromosome, called the centromere, might help direct chromosomes movements, in doing so helping to prevent the errors that lead to birth defects.

描述（由申请人提供）：在过去的三十年中，文献中有零星的关于减数分裂两个不同阶段的同源和非同源染色体着丝粒之间配对的报道。首先，对多种生物（洋葱、小麦、芽殖酵母、小鼠）的研究表明，在减数分裂早期，DNA 复制后，着丝粒会成对排列。这种配对主要发生在非同源着丝粒之间。当同源染色体在减数分裂前期对齐时，这种非同源的早期减数分裂着丝粒配对就会消失。其次，着丝粒也可以在减数分裂的后期主动配对。例如，对芽殖酵母和雌性果蝇的研究表明，未能重组的伴侣染色体（非交换染色体）在前期后期在着丝粒（或着丝粒周围异染色质）处配对，此时同源染色体完全突触。非交换伙伴之间的减数分裂晚期着丝粒配对促进了它们在第一次减数分裂时的分离。在芽殖酵母中，着丝粒配对的早期和晚期都依赖于联会复合体 (SC) 蛋白 Zip1。该项目旨在表征减数分裂中着丝粒配对的两个阶段，测试它们在机制上是否相关或不同，并确定它们如何影响减数分裂 I 中染色体的分离。因为减数分裂着丝粒配对的观察是从如此多样化的过程中收集的范围广泛的实验生物体，所提出的实验可能揭示减数分裂染色体行为的保守但基本上未被识别的方面的细节。该项目分为五组实验。第一组实验确定了减数分裂早期与着丝粒相关的 Zip1 区域，并使用亲和纯化方法来鉴定参与着丝粒配对早期的蛋白质。人们对着丝粒早期配对到晚期着丝粒配对的转变知之甚少。第二组实验将探索这种转变并阐明这两个阶段的关系。在最终旨在配对然后分离同源染色体的过程（减数分裂 I）开始时对齐非同源着丝粒的目的是什么？第三组实验检验了非同源着丝粒配对阻止着丝粒附近交叉形成的假设。已知这种交换会破坏许多生物体中减数分裂 I 染色体分离的保真度。最后两组实验将首先探讨 Zip1 如何在减数分裂前期促进着丝粒配对，其次将检验这种晚期着丝粒配对促进着丝粒附着到减数分裂 I 纺锤体相反两极的假设，并在这样做，在重要方面有助于减数分裂 I 分离保真度。 公共健康相关性：将染色体分配给配子的过程中的错误是出生缺陷的主要原因。该项目使用芽殖酵母来识别未被发现的方式，染色体的一个组成部分（称为着丝粒）可能有助于指导染色体运动，从而有助于防止导致出生缺陷的错误。