Chromosome structural variants in meiosis

项目摘要 在减数分裂过程中，通过重组产生杂交，确保了染色体的精确分离 (COs)同源染色体之间。DNA双链断裂（DSB）引发了DNA断裂。 可以作为CO或非交叉（NCO）进行修复，但如何将任何给定的DSB指定为CO或NCO 尽管对所涉及的遗传网络有了详细的了解，但修复仍然是个谜。在 目前的建议，我们描述了我们的方法来解决如何CO/NCO的决定，以及如何 全基因组CO模式化机制局部作用于DSB以影响修复结果。我们将使用 染色体结构变异作为操纵果蝇DSB修复结果的系统。 我们最近发现29杂合倒位抑制了倒位断点外的CO， 改变修复结果，有利于NCOs，同时引发全基因组范围内的COs增加 通过改变修复结果来支持CO。我们正在根据这些结果建立两个研究领域。第一、 我们正在探索杂合倒位是如何通过携带 对这些抑制区的重组进行遗传分析。这种遗传分析有两个部分， 候选基因方法寻找改变近倒位CO和NCO分布的基因 断裂点，以及重组事件的分子遗传学分析，以确定 路径使用。我们将对这些研究采取补充方法，并使用Hi-C和Super- 分辨率成像，询问是否有局部染色体结构和/或联会复合体的变化， 反转断点。我们的第二个研究领域将探讨杂合倒位如何触发基因组- CO的大幅增长。为了确定介导这种增加的机制，我们将对细胞进行细胞学分析。 杂合倒位中CO形成的动力学，确定正常的CO模式化机制是否 绕过以促进CO的增加，并确定哪些重组途径用于 增加的CO。总之，我们将利用我们对杂合倒位如何影响 将CO/NCO决定转化为一般模型，解决减数分裂重组和交叉模式如何 相交形成最终的重组景观此外，这些实验将阐明如何 结构变异导致染色体非整倍性和随后的人类不育。

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.