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）：大多数性繁殖生物中配子的形成涉及受控基因组碎片和改组称为减数分裂重组的阶段。除了促进遗传多样性之外，DNA序列的交换还可以与绑带同源染色体，这对于控制成精子或卵子的染色体分类至关重要。减数分裂重组是由DNA双链断裂（DSB）引发的。由于DSB固有地很难修复，因此必须严格调节减数分裂的DSB形成，以防止基因组重排，异常的配子和出生缺陷。该项目的总体目标是定义将减数分裂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后果。减数分裂DSB的控制将在性繁殖的酵母酵母酿酒酵母中进行研究。该项目的初步研究确定了活性减数分裂DSB抑制的两种机制：（i）DSB形成会响应延迟DNA复制而减弱，（ii）DSB在高度重复的核糖体DNA（RDNA）附近受到组成抑制。这些研究还表明，DNA复制与DSB形成之间的耦合是专门检查点机制的结果，并且已经确定了该检查点的一个组成部分。提出的实验将使用分子生物学，遗传和基因组方法来定义该检查点如何调节减数分裂DSB机械并确定其他检查点成分。初步研究还确定了在rDNA附近抑制DSB所需的保守蛋白质，并提出了染色体结构在此过程中的重要作用。提出的实验将定义rDNA附近的减数分裂染色体结构，并确定该蛋白对DSB机械局部活性的影响。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重复稳定性的后果。 公共卫生相关性： 不适当的减数分裂重组引起的染色体分类中的基因组重排和误差与各种出生缺陷有关，包括唐氏综合症，威廉姆斯综合征和普拉德·威利综合征。通过定义控制减数分裂重组开始的分子机制，该项目将为保护配子生产过程中保护染色体完整性的机制提供重大见解，并将作为研究人类出生缺陷的重要框架。