Genetic Recombination in C. elegans

项目总结： 我们的长期目标是阐明基因重组如何有助于忠实地继承 减数分裂过程中的染色体，是二倍体生物产生的特殊细胞分裂程序 单倍体配子。减数分裂过程中染色体遗传依赖于双链DNA的形成 中断(DSB)并将这些DSB的子集修复为同源间交叉(CoS)。未能形成 COS导致染色体错误分离和随之而来的非整倍体，这是导致 人类的流产和出生缺陷。因为作为减数分裂启动事件的双链断裂 重组对基因组完整性、减数分裂过程中基因组遗传的成功构成威胁 要求细胞在CoS的有益影响和潜在的有害影响之间保持平衡 它们产生的过程的后果。我们的目标是了解 在减数分裂期间进行操作，以实现这一关键的平衡。我们正在使用 线虫线虫，一种简单的后生动物有机体，特别容易结合复杂的 在单个实验系统中的细胞学、遗传学和基因组学方法，其中事件 正在研究的是特别容易获得和健壮的。拟议的工作将利用最近的进展， 提供在活的和固定的生殖细胞中标记新生CO事件的位置的方法，以量化 CO干扰的强度，在DNA水平和 组织倍性，以可视化和揭示以前无法获得的DNA修复的组织特征 在重组位点组装的复合体，并获得高质量的基因组信息 染色质由少量细胞组成。一个目标是阐明体系结构和 在减数分裂重组的体内部位组织DNA修复复合体，目的是 单个重组蛋白/复合体活性之间的推演和协调关系 以及集体一氧化碳重组机制的体内功能。另一个目标是理解 促进和限制减数分裂CoS形成的机制，都是在指定重组的水平上 CO或非CO命运的场所，以及执行这些命运的可靠执行的水平。最后，我们会 研究促进形成足够的DSB以保证CO形成的过程，以及 有效地将这些DSB引导到基于同源重组的修复途径中，并远离错误- 容易发生突变的修复途径。

Project Summary: Our long term goal is to elucidate how genetic recombination contributes to the faithful inheritance of chromosomes during meiosis, the specialized cell division program by which diploid organisms generate haploid gametes. Chromosome inheritance during meiosis relies on the formation of double-strand DNA breaks (DSBs) and repair of a subset of these DSBs as inter-homolog crossovers (COs). Failure to form COs leads to chromosome missegregation and consequent aneuploidy, one of the leading causes of miscarriages and birth defects in humans. Because the DSBs that serve as the initiating events of meiotic recombination pose a danger to genome integrity, the success of genome inheritance during meiosis requires cells to maintain a balance between the beneficial effects of COs and the potential harmful consequences of the process by which they are generated. Our goal is to understand the mechanisms that operate during meiosis to achieve this crucial balance. We are approaching this problem using the nematode C. elegans, a simple metazoan organism that is especially amenable to combining sophisticated cytological, genetic and genomic approaches in a single experimental system, and in which the events under study are particularly accessible and robust. The proposed work will exploit recent advances that provide the means to mark the sites of nascent CO events in live and fixed germ cells, to quantify the strength of CO interference, to manipulate the genome efficiently both at the DNA level and at the level of organismal ploidy, to visualize and reveal previously inaccessible organizational features of the DNA repair complexes assembled at recombination sites, and to obtain high-quality genome-wide information on chromatin organization from small numbers of cells. One goal is to elucidate the architecture and organization of DNA repair complexes at in vivo sites of meiotic recombination, with the objective of deducing and reconcilng relationships between the activities of individual recombination proteins/complexes and the in vivo functions of the collective CO recombination machinery. Another goal is to understand the mechanisms that promote and limit formation of meiotic COs, both at the level of designating recombination sites for a CO or non-CO fate and at the level of enforcing reliable execution of these fates. Finally, we will investigate processes that promote the formation of sufficient DSBs to guarantee CO formation and that efficiently channel these DSBs into homologous-recombination based repair pathways and away from error- prone mutagenic repair pathways.