Chromosome structural variants in meiosis

项目摘要 通过重组创造交叉，确保了减数分裂过程中准确的染色体分离 (Cos)在同源染色体之间。重组由DNA双链断裂(DSB)启动 这可以作为CO或非交叉(NCO)进行修复，但如何为CO或NCO指定任何给定的DSB 尽管对所涉及的遗传网络有了详细的了解，修复仍然是一个谜。在 目前的提案，我们描述了我们如何处理CO/NCO决策是如何做出的，以及如何 全基因组的CO模式形成机制在DSB局部作用，影响修复结果。我们将使用 染色体结构变异作为操纵黑腹果蝇DSB修复结果的系统。 我们最近发现29杂合性反转通过以下方式在反转断点外局部抑制CoS 改变修复结果，有利于NCO，并同时引发全基因组COS的增加 通过改变维修结果以支持CoS。基于这些结果，我们正在建设两个研究领域。第一, 我们正在探索杂合子倒置如何通过携带DSB修复CO修复结果 对这些抑制区的重组进行了遗传分析。这种遗传分析有两个部分，一个是 寻找在倒位附近改变COS和NCOS分布的候选基因方法 断点，以及重组事件的分子遗传分析，以确定哪些重组 使用了路径。我们将对这些研究采取补充方法，并使用Hi-C和Super-C 分辨率成像检查是否有局部染色体结构和/或联会复合体改变 反转断点。我们的第二个研究领域将询问杂合子倒置如何触发基因组- 成本大幅增长。为了确定调节这种增加的机制，我们将通过细胞学分析 杂合反转中的CO生成动力学，确定正常的CO图案化机制是否 绕过，以促进CoS的增加，并确定使用哪些重组途径来 形成增加的CoS。总而言之，我们将利用我们对杂合反转如何影响的理解 将CO/NCO决策转化为解决减数分裂重组和交叉模式的一般模型 相交以创建最终的重组景观。此外，这些实验将阐明如何 结构变异导致人类染色体非整倍体和随后的不孕不育。

Project Summary Accurate chromosome segregation during meiosis is ensured by using recombination to create crossovers (COs) between homologous chromosomes. Recombination is initiated by a DNA double-stranded break (DSB) that can be repaired either as a CO or a noncrossover (NCO), but how any given DSB is slated for CO or NCO repair has remained enigmatic despite a detailed understanding of the genetic networks involved. In the current proposal, we describe our approach for addressing how the CO/NCO decision is made and how genome-wide CO patterning mechanisms act locally at a DSB to influence repair outcome. We will use chromosome structural variants as a system for manipulating DSB repair outcome in Drosophila melanogaster. We recently showed29 that heterozygous inversions suppress COs locally outside the inversion breakpoint by altering repair outcome in favor of NCOs and that they simultaneously trigger a genome-wide increase in COs by altering repair outcome in favor of COs. We are building two research areas based on these results. First, we are exploring how heterozygous inversions shuttle DSB repair away from a CO repair outcome by carrying out a genetic analysis of recombination in these zones of suppression. This genetic analysis has two parts, a candidate gene approach to look for genes that change the distribution of COs and NCOs near inversion breakpoints, and a molecular genetic analysis of recombination events to determine which recombination pathways are used. We will take a complementary approach to these studies and use Hi-C and super- resolution imaging to ask if there are local chromosome structure and/or synaptonemal complex changes at the inversion breakpoint. Our second research area will ask how heterozygous inversions trigger a genome- wide increase in COs. To determine the mechanisms that mediate this increase, we will cytologically assay the kinetics of CO formation in heterozygous inversions, determine if normal CO patterning mechanisms are bypassed in order to facilitate the increase in COs, and determine which recombination pathways are used to form the increased COs. In sum, we will leverage our understanding of how heterozygous inversions influence the CO/NCO decision into general models that address how meiotic recombination and crossover patterning intersect to create the final recombination landscape. Furthermore, these experiments will elucidate how structural variants lead to chromosome aneuploidy and subsequent infertility in the human population.