Control of meiotic double strand break formation

减数分裂双链断裂形成的控制

• 批准号: 8535164
• 负责人: Andreas Hochwagen
• 金额: $ 28.53万
• 依托单位: NEW YORK UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-30 至 2015-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8535164
• 关键词: ATP phosphohydrolase; Attenuated; Biological; Biological Assay; Boundary Elements; Chromatin; Chromosome Structures; Chromosomes; Congenital Abnormality; Coupling; Cues; DNA; DNA Double Strand Break; DNA Sequence; DNA Sequence Rearrangement; DNA biosynthesis; Data; Defect; Diploidy; Double Strand Break Repair; Down Syndrome; Failure; Genetic; Genetic Recombination; Genetic Variation; Genome; Genome Stability; Genomics; Germ Cells; Goals; Haploidy; Human; Infertility study; Licensing; Location; Meiosis; Meiotic Recombination; Modeling; Molecular; Organism; Phosphotransferases; Prader-Willi Syndrome; Preparation; Process; Production; Proteins; Replication Initiation; Research; Ribosomal DNA; Role; Saccharomyces cerevisiae; Saccharomycetales; Sister Chromatid; Staging; Testing; Time; Williams Syndrome; Yeasts; attenuation; egg; genome-wide; hydroxyurea; improved; insight; premature; prevent; progenitor; public health relevance; repaired; research study; response; sperm cell

DESCRIPTION (provided by applicant): The formation of gametes in most sexually reproducing organisms involves a stage of controlled genome fragmentation and reshuffling known as meiotic recombination. Aside from promoting genetic diversity, the exchange of DNA sequences serves to tether homologous chromosomes, which is essential for controlled chromosome assortment into sperm or eggs. Meiotic recombination is initiated by DNA double strand breaks (DSBs). Because DSBs are inherently difficult to repair, meiotic DSB formation must be tightly regulated to prevent genome rearrangements, aberrant gametes, and birth defects. The overall goal of this project is to define the molecular mechanisms that restrict meiotic DSBs to the appropriate times and genomic locations, and to determine the consequences of inappropriate meiotic DSB formation on DSB repair and genome stability. Meiotic DSB control will be investigated in the sexually reproducing yeast Saccharomyces cerevisiae. Preliminary studies for this project identified two mechanisms of active meiotic DSB suppression: (i) DSB formation is attenuated in response to delayed DNA replication, (ii) DSBs are constitutively suppressed in the vicinity of the highly repetitive ribosomal DNA (rDNA). Those studies furthermore suggested that the coupling between DNA replication and DSB formation is the consequence of a specialized checkpoint mechanism and one component of this checkpoint has been identified. The proposed experiments will use molecular biological, genetic, and genomic approaches to define how this checkpoint regulates the meiotic DSB machinery and to identify additional checkpoint components. Preliminary studies also identified a conserved protein required for the suppression of DSBs in the vicinity of the rDNA and suggested an important role for chromosome structure in this process. The proposed experiments will define the meiotic chromosome structure near the rDNA and determine the effect of this protein on the local activity of the DSB machinery. In addition, genetic assays and physical analysis of repair intermediates will be used to determine the consequences of inappropriate DSB formation on meiotic genome integrity and rDNA repeat stability. PUBLIC HEALTH RELEVANCE: Genome rearrangements and errors in chromosome assortment resulting from inappropriate meiotic recombination are associated with a variety of birth defects, including Down syndrome, Williams syndrome, and Prader-Willi syndrome. By defining the molecular mechanisms that control the initiation of meiotic recombination, this project will provide significant insight into the mechanisms that protect chromosomal integrity during gamete production and will serve as an important framework for the study of birth defects in humans.

描述（由申请人提供）：大多数有性生殖生物体中配子的形成涉及受控基因组断裂和重组的阶段，称为减数分裂重组。除了促进遗传多样性之外，DNA 序列的交换还可以束缚同源染色体，这对于受控染色体分类为精子或卵子至关重要。减数分裂重组是由 DNA 双链断裂 (DSB) 启动的。由于 DSB 本质上难以修复，减数分裂 DSB 的形成必须受到严格调控，以防止基因组重排、异常配子和出生缺陷。该项目的总体目标是确定将减数分裂 DSB 限制在适当时间和基因组位置的分子机制，并确定不适当的减数分裂 DSB 形成对 DSB 修复和基因组稳定性的影响。将在有性繁殖的酿酒酵母中研究减数分裂 DSB 控制。该项目的初步研究确定了主动减数分裂 DSB 抑制的两种机制：(i) DSB 形成因 DNA 复制延迟而减弱，(ii) DSB 在高度重复的核糖体 DNA (rDNA) 附近受到组成性抑制。这些研究进一步表明，DNA 复制和 DSB 形成之间的耦合是一种特殊检查点机制的结果，并且该检查点的一个组成部分已被识别。拟议的实验将使用分子生物学、遗传学和基因组方法来定义该检查点如何调节减数分裂 DSB 机制并识别其他检查点组件。初步研究还发现了抑制 rDNA 附近 DSB 所需的保守蛋白，并表明染色体结构在此过程中发挥着重要作用。拟议的实验将定义 rDNA 附近的减数分裂染色体结构，并确定该蛋白质对 DSB 机器局部活性的影响。此外，修复中间体的遗传测定和物理分析将用于确定不适当的 DSB 形成对减数分裂基因组完整性和 rDNA 重复稳定性的影响。 公共卫生相关性： 不适当的减数分裂重组导致的基因组重排和染色体分类错误与多种出生缺陷有关，包括唐氏综合症、威廉姆斯综合症和普瑞德威利综合症。通过定义控制减数分裂重组启动的分子机制，该项目将为配子产生过程中保护染色体完整性的机制提供重要的见解，并将作为研究人类出生缺陷的重要框架。