Mechanism and regulation of meiotic recombination

减数分裂重组的机制和调控

• 批准号: 10393654
• 负责人: Scott Keeney
• 金额: $ 46.36万
• 依托单位: SLOAN-KETTERING INST CAN RESEARCH
• 依托单位国家: 美国
• 财政年份: 2016
• 资助国家: 美国
• 起止时间: 2016-05-01 至 2026-04-30
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10393654
• 关键词: Address; Area; Behavior; Biological Assay; Biology; Cells; Chromatin; Chromosomes; Complex; DNA; DNA Damage; DNA Double Strand Break; DNA Sequence; Defect; Developmental Disabilities; Double Strand Break Repair; Ensure; Evolution; Excision; Genetic Recombination; Genome; Genome Stability; Genomics; Heritability; Human; Location; Mammals; Meiosis; Meiotic Recombination; Methods; Molecular; Mus; Mutation; Nucleotides; Outcome; Pathway interactions; Process; Pseudoautosomal Region; Regulation; Reproductive Health; Research; Resolution; Risk; Role; SPO11 gene; Saccharomyces cerevisiae; Sex Chromosomes; Sexual Reproduction; Shapes; Spontaneous abortion; Sterility; Structure; Testing; Time; Trans-Activators; Work; X Chromosome; Y Chromosome; Yeasts; ataxia telangiectasia mutated protein; chromosome missegregation; chromosome number abnormality; egg; genome integrity; genome-wide; homologous recombination; innovation; male; nuclease; offspring; programs; repaired; reproductive system disorder; response; risk minimization; segregation; sperm cell; tool; whole genome

Homologous recombination in meiosis is essential for genome integrity during sexual reproduction, but is also a powerful determinant of genome evolution and puts cells at risk for mutation and chromosome rearrangements. Meiotic recombination initiates with DNA double-strand breaks (DSBs) made by Spo11. Cells ensure that DSBs are made at the right times, places, and numbers to maximize repair efficiency and minimize risks of deleterious outcomes. This research program aims to understand the molecular mechanisms of meiotic DSB formation and of the processes that regulate DSBs and recombination. Mouse and the yeast S. cerevisiae will be used to explore these critical aspects of chromosome biology. Specific areas of inquiry include the following: · A complex network of pathways controls the number, timing, and distribution of DSBs. In one pathway, the DNA damage-response kinase ATM inhibits formation of additional breaks. A second pathway suppresses DSB formation in places where homologous chromosomes have successfully engaged one another. An important challenge is to understand the mechanisms underlying these pathways. · DSB locations are nonrandom, and this DSB “landscape” has important consequences for heritability and genome stability. The factors shaping the DSB landscape remain poorly understood, but recent advances inform mechanistic hypotheses about the roles of both chromosome-intrinsic and trans-acting factors. These hypothe- ses will be tested using powerful methods for mapping DSB distributions genome-wide at nucleotide resolution. · An essential step in the repair of DSBs by recombination is the exonucleolytic processing of DNA ends, but little is known about the mechanism. An innovative new whole-genome assay for DSB resection will be exploited to define how resection is carried out, how it is regulated, and how it overcomes the barrier to nucleases posed by chromatin. · Erroneous, non-allelic recombination between repetitive DNA sequences yields chromosome rearrange- ments that can be passed on to offspring. Recent work identified genomic locations in mice that are prone to such errors and developed tools to characterize and quantify rearrangements. Important challenges now are to understand the mechanisms of this mutagenic recombination and to understand how cells avoid these errors. · In male mammals, segregation of the sex chromosomes is especially challenging because the X and Y chro- mosomes share only a small region of homology (the pseudoautosomal region, or PAR) within which recombi- nation must occur. Defects in PAR recombination cause sterility or sex chromosome missegregation. Recent work has revealed that the PAR develops complex, dynamic structures during meiosis. Cis- and trans-acting factors critical for this behavior have also been uncovered. Key questions will be addressed concerning the mechanisms that ensure sex chromosome recombination and segregation.

减数分裂中的同源重组对于有性生殖过程中的基因组完整性至关重要，但也是一种 基因组进化的强大决定因素，并使细胞面临突变和染色体重排的风险。 减数分裂重组以 Spo11 细胞产生的 DNA 双链断裂 (DSB) 启动。 在正确的时间、地点和数量进行，以最大限度地提高修复效率并最大限度地降低有害风险 该研究项目旨在了解减数分裂 DSB 形成的分子机制和 调节 DSB 和重组的过程将被用于小鼠和酿酒酵母。 探索染色体生物学的这些关键方面，具体的研究领域包括： · 一个复杂的通路网络控制着 DSB 的数量、时间和分布。 DNA 损伤反应激酶 ATM 抑制额外断裂的形成 第二条途径抑制 DSB。 在同源染色体成功相互接合的地方形成这一点很重要。 挑战在于了解这些途径背后的机制。 · DSB 位置是非随机的，这种 DSB“景观”对遗传力和 影响 DSB 格局的因素仍然知之甚少，但最近的进展表明了这一点。 关于染色体内在因子和反式作用因子的作用的机制假设。 ses 将使用强大的方法进行测试，以核苷酸分辨率绘制全基因组 DSB 分布图。 · 通过重组修复 DSB 的一个重要步骤是 DNA 末端的核酸外切加工，但是 我们对这种机制知之甚少，我们将利用一种创新的全基因组检测来进行 DSB 切除。 定义如何进行切除、如何监管以及如何克服核酸酶造成的障碍 通过染色质。 · 重复 DNA 序列之间的错误、非等位基因重组会产生染色体重排 - 最近的工作确定了小鼠中易于遗传的基因组位置。 现在重要的挑战是解决此类错误并开发表征和量化重排的工具。 这种诱变重组的机制并了解细胞如何避免这些错误。 · 在雄性哺乳动物中，性染色体的分离尤其具有挑战性，因为 X 和 Y 染色体 微粒体仅共享一个小区域的同源性（伪常染色体区域，或 PAR），在该区域内重组 PAR 重组缺陷会导致不育或性染色体错误分离。 研究表明，PAR 在减数分裂过程中形成复杂的动态结构。 对于这种行为的关键因素也已被发现，有关的关键问题也将得到解决。 确保性染色体重组和分离的机制。