Recombination pathway and partner choices during meiosis

研究综述 染色体间的相互作用是产生遗传变异、维持基因组完整性的必要条件 通过修复双链DNA断裂（DSB），并确保染色体在 减数分裂，二倍体生物产生单倍体配子的专门细胞分裂程序， 精子和卵子重组中的扰动最终会损害这些基本的细胞功能， 导致癌症不孕不育或出生缺陷减数分裂重组由DSB启动，DSB被修复， 利用有利于利用同源染色体（而不是姐妹染色体）的减数分裂特异性机制 染色单体）作为重组配偶体，并促进DSB修复过程的交叉结果， 这是在减数分裂期间促进适当的染色体分离所必需的。虽然DSB的修复 适当的模板（同源染色体）对于正确的染色体分离是必需的， 基因组的完整性，我们关于生殖细胞如何在存在下实现这种模板偏好的知识， 几乎相同的序列（姐妹染色单体）是有限的。以秀丽隐杆线虫为模型系统， 已经开发了一种荧光测定法，用于监测诱导的DSB与姐妹染色单体的修复， 体内减数分裂前期进展。资助赠款的主要目标之一是使用这种测定方法， 确定这些不同的修复合作伙伴的选择是如何监管的。来可视化蛋白质的定位 以及与活的和固定的生殖细胞中的DSB修复和染色体结构相关的标记物， 完整的C。elegans，我们利用一个宽视野反卷积显微镜。最近，LED光源 这台至关重要的显微镜突然失去了功能，需要更换。我们所有的实验 与此授权相关的所有设备都处于停顿状态，直到更换LED光源。该补充将支持 购买显微镜功能所需的替换LED光源。总体看 所要求的光源更换对我们的研究计划至关重要，将使我们能够实现我们的目标。 目的是确定与这些不同的基因相关的分子特征、染色体特征和蛋白质。 修复结果是维持精子和卵子发育过程中基因组完整性的核心。

Research Summary Recombination between chromosomes is required to generate genetic variation, maintain genome integrity through the repair of double strand DNA breaks (DSBs), and ensure proper chromosome segregation during meiosis, the specialized cell division program by which diploid organisms generate haploid gametes such as sperm and eggs. Perturbations in recombination can compromise these basic cellular functions, ultimately leading to cancer, infertility, or birth defects. Meiotic recombination is initiated by DSBs, which are repaired using meiosis-specific mechanisms that favor utilization of the homologous chromosome (instead of the sister chromatid) as the recombination partner and that promote a crossover outcome of the DSB repair process, which is required for promoting proper chromosome segregation during meiosis. Although repair of DSBs with the appropriate template (homologous chromosome) is necessary for proper chromosome segregation and genome integrity, our knowledge about how germ cells achieve this template preference in the presence of nearly identical sequences (sister chromatids) is limited. Using Caenorhabditis elegans as a model system, we have developed a fluorescent assay to monitor repair of an induced DSB with the sister chromatid during meiotic prophase progression in vivo. One of the primary goals of the funded grant is to use this assay to determine how these different repair partner choices are regulated. To visualize the localization of proteins and markers associated with DSB repair and chromosome structures in both live and fixed germ cells and whole intact C. elegans, we utilize a widefield deconvolution microscope. Recently, the LED light source for this critical microscope suddenly became nonfunctional and requires replacement. All of our experiments associated with this grant are at standstill until the LED light source is replaced. This supplement will support the purchase of replacement LED light source that is required for function of the microscope. Overall, the requested light source replacement is essential for our research program and will enable us to achieve our goals to identify the molecular signatures, chromosomal features, and proteins associated with these different repair outcomes that are central to maintaining genomic integrity during sperm and egg development.