Mechanisms of Chromosome Scale Signal Propagation

染色体尺度信号传播的机制

• 批准号: 10217794
• 负责人: Andreas Hochwagen
• 金额: $ 4.09万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-03-01 至 2023-05-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10217794
• 关键词: ATP phosphohydrolase; Animal Model; Binding; Birds; Cells; Chromatin; Chromosomal Breaks; Chromosomal Instability; Chromosome Segregation; Chromosomes; Communication; Congenital Abnormality; Cytology; DNA; DNA Double Strand Break; Dangerousness; Data; Defect; Double Strand Break Repair; Down Syndrome; Down-Regulation; Edward' s syndrome; Ensure; Event; Fertility; Funding; Genes; Genetic; Genetic Epistasis; Genetic Nondisjunction; Genetic Recombination; Genetic Transcription; Genetic Variation; Genome; Genomic Segment; Genomics; Germ Cells; Goals; Human; Human Chromosomes; Incidence; Infertility; Lead; Length; Mammals; Meiosis; Meiotic Recombination; Microscopy; Modeling; Molecular; Nuclear; Nuclear Envelope; Nuclear Pore; Organism; Pan Genus; Pattern; Process; Production; Prophase; Proteins; Regulation; Research; Resistance; Resolution; Rest; Risk; Role; Saccharomyces cerevisiae; Signal Transduction; Structure; Synaptonemal Complex; Testing; Work; Yeasts; egg; enzyme activity; experimental study; genome integrity; genome-wide analysis; improved; insight; interstitial; novel; repaired; segregation; sperm cell; telomere; tumor progression

Project summary The overall goal of this project is to determine how cells communicate chromosome break formation and repair across large chromosomal distances. DNA double-strand breaks (DSBs) are dangerous insults to genome integrity because of their potential to cause chromosome rearrangements and chromosome instability, both of which are strongly associated with cancer progression as well as birth defects. Remarkably, meiotic cells are able to efficiently orchestrate the formation and repair of hundreds of concurrent DSBs across their genome during meiotic recombination, a process that is essential for proper gamete formation and fertility. A key feature of meiotic DSB formation and repair is its coordination at the chromosomal level. In the previous funding period we provided evidence that the synaptonemal complex, a conserved protein lattice that forms between aligned homologous chromosomes in late meiotic prophase, communicates repair decisions along meiotic chromosomes in S. cerevisiae. We showed that this communication resulted in reduced DSB formation as well as simplified repair, and we identified several factors involved in this process. We now discovered the existence of privileged genomic regions near the ends of all chromosomes that appear resistant to regulation by the synaptonemal complex. These end-adjacent regions (EARs) cover large genomic distances (~100kb, which is nearly half the length of the shortest chromosome) and continue to form and repair DSBs well after DSB formation has stopped in the rest of the genome. Similar regions of elevated meiotic recombination are also observed in birds, chimps, and humans. The goal of this project is to define the chromosomal signal that generates these regions and to test if EARs help inheritance of short chromosomes. Our preliminary analyses suggest several roles of the nuclear envelope, both in the establishment of the EARs and in the suppression of DSBs in the rest of the genome. The dynamics of chromosomal signaling and its interaction with the nuclear envelope will be analyzed by genome-wide binding studies and super-resolution microscopy, taking advantage of a conditional nuclear depletion approach that we recently introduced into meiotic cells that allows stage-specific knock-downs of pleiotropic nuclear factors. In addition, signal integration will be analyzed using genetic epistasis analyses, cytology, and physical analysis of DSB formation. As EARs cover a proportionally much larger fraction of short chromosomes, the proposal will also use tetrad sequencing to test if these regions drive the widely observed increase in recombination rates on short chromosomes. Fluorescent marker segregation will be used to determine if EARs differentially improve the meiotic segregation fidelity of short chromosomes. Together, these analyses will provide key insights into the mechanisms of chromosomal signal propagation, and open new avenues for understanding the origins of birth defects such as Down syndrome (trisomy 21) and Edwards syndrome (trisomy 18), which are caused by meiotic missegregation of short chromosomes.

项目概要 该项目的总体目标是确定细胞如何传达染色体断裂形成和 跨大染色体距离的修复。 DNA 双链断裂 (DSB) 是对人类的危险侮辱 基因组完整性，因为它们有可能导致染色体重排和染色体不稳定， 两者都与癌症进展以及出生缺陷密切相关。值得注意的是，减数分裂 细胞能够有效地协调其体内数百个并发 DSB 的形成和修复 减数分裂重组期间的基因组，这一过程对于正确的配子形成和生育力至关重要。 减数分裂 DSB 形成和修复的一个关键特征是其在染色体水平上的协调。在 在之前的资助期间，我们提供的证据表明，联会复合体（一种保守的蛋白质晶格） 在减数分裂晚期对齐的同源染色体之间形成，传达修复决策 沿着酿酒酵母的减数分裂染色体。我们证明这种沟通导致 DSB 减少 形成以及简化修复，我们确定了此过程中涉及的几个因素。我们现在 发现所有似乎具有抗性的染色体末端附近存在特殊基因组区域 受联会复合体的调节。这些末端相邻区域 (EAR) 覆盖大型基因组 距离（~100kb，几乎是最短染色体长度的一半）并继续形成和修复 DSB 在 DSB 形成很久之后就已经在基因组的其余部分中停止了。减数分裂升高的相似区域 在鸟类、黑猩猩和人类中也观察到重组。 该项目的目标是定义生成这些区域的染色体信号并测试是否 EAR 有助于短染色体的遗传。我们的初步分析表明核的几个作用 包膜，无论是在 EAR 的建立还是在基因组其余部分中 DSB 的抑制中。 染色体信号的动态及其与核膜的相互作用将通过以下方式进行分析 全基因组结合研究和超分辨率显微镜，利用条件核 我们最近引入减数分裂细胞的耗尽方法，允许阶段特异性的敲低 多效性核因子。此外，将使用遗传上位分析来分析信号整合， DSB 形成的细胞学和物理分析。由于 EAR 涵盖的空头比例要大得多 染色体，该提案还将使用四分体测序来测试这些区域是否驱动广泛观察到的 短染色体重组率增加。荧光标记分离将用于 确定 EAR 是否有差异地提高短染色体减数分裂分离的保真度。在一起，这些 分析将为染色体信号传播机制提供重要见解，并开辟新的领域 了解唐氏综合症（21 三体症）和爱德华兹等先天缺陷起源的途径 综合征（18 三体），由短染色体减数分裂错误分离引起。