Recombination pathway and partner choices during meiosis

研究总结 染色体之间的重组是产生遗传变异、维持基因组完整性所必需的 通过修复双链DNA断裂(DSB)，并确保在 减数分裂，二倍体生物产生单倍体配子的特殊细胞分裂程序，如 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、不孕不育或先天缺陷。减数分裂重组是由DSB启动的，DSB被修复 使用有利于利用同源染色体(而不是姊妹染色体)的减数分裂特定机制 染色单体)作为重组伙伴并且促进DSB修复过程的交叉结果， 这是在减数分裂过程中促进适当的染色体分离所必需的。虽然使用DSB修复DSB 适当的模板(同源染色体)对于正确的染色体分离和 基因组完整性，我们关于生殖细胞如何在存在 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，我们 我开发了一种荧光分析方法来监测诱导的DSB与姐妹染色单体在 体内减数分裂前期进展。资助赠款的主要目标之一是利用这种分析来 确定如何规范这些不同的维修合作伙伴选择。使蛋白质的定位可视化 在活的和固定的生殖细胞中与DSB修复和染色体结构相关的标记和 完整的线虫，我们利用宽视场去卷积显微镜。最近，用于照明的LED光源 这台关键的显微镜突然不能工作了，需要更换。我们所有的实验 在更换LED光源之前，与此拨款相关的所有设备都处于停顿状态。本增刊将支持 购买显微镜运行所需的更换LED光源。总体而言， 所要求的光源更换对于我们的研究计划是必不可少的，并将使我们能够实现 目的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 修复对在精子和卵子发育过程中保持基因组完整性至关重要的结果。

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.