Recombination pathway and partner choice during C. elegans meiosis

线虫减数分裂过程中的重组途径和伴侣选择

• 批准号: 9001589
• 负责人: Diana Elizabeth Libuda
• 金额: $ 24.9万
• 依托单位: UNIVERSITY OF OREGON
• 依托单位国家: 美国
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-01-30 至 2015-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9001589
• 关键词: Address; Biological Assay; Caenorhabditis elegans; Cell division; Cell physiology; Cells; Chromosomal Breaks; Chromosome Segregation; Chromosome Structures; Chromosomes; Congenital Abnormality; Cytological Techniques; DNA; DNA Damage; DNA Double Strand Break; DNA Repair; Data; Development; Diploidy; Double Strand Break Repair; Ensure; Event; Fertility; Foundations; Genetic Recombination; Genetic Techniques; Genetic Variation; Genetic study; Germ Cells; Goals; Gonadal structure; Haploidy; Health; Homologous Gene; Human; Image; Life; Malignant Neoplasms; Meiosis; Meiotic Recombination; Monitor; Optic Chiasm; Organism; Other Genetics; Outcome; Pathway interactions; Phase; Positioning Attribute; Process; Prophase; Protein Isoforms; Proteins; Publishing; Reagent; Research; Role; Sister Chromatid; Site; Staging; System; Testing; Time; Work; egg; genome integrity; new technology; novel; preference; premature; prevent; programs; recombinase; recombinational repair; repaired; restoration; segregation; sperm cell

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 events can compromise these basic cellular functions, ultimately leading to cancer, fertility problems, 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 (rather than noncrossover) outcome of the DSB repair (DSBR) process. Crossover recombination between homologous chromosomes is required to create temporary physical connections that promote proper chromosome segregation during meiosis. In order to promote these recombination pathway and partner preferences required for generating crossovers between homologous chromosomes, germ cells engage a specialized DSBR program at the onset of meiotic prophase. During late meiotic prophase, meiotic cells undergo a second switch in the DSBR requirements, which is proposed to revert to utilization of repair preferences typical of mitotically dividing cells (e.g. favoring the sister chromatid as the repair partner). This proposed switch would enable repair of any remaining DSBs prior to the meiotic divisions, thereby preserving genomic integrity. Utilizing the C. elegans experimental system, the proposed studies will address how different recombination pathways and partners are employed during meiosis to both promote crossover formation between homologs and repair any remaining DSBs prior to the meiotic divisions. To assess the temporal and mechanistic features of these pathway and partner choices, I will expand the scope of our recently published assay system by developing an assay to detect and distinguish the different repair products of DSBs induced at a defined site. With this assay, I will directly test for the hypothesized switch in partner preference during meiotic prophase progression and determine the effect of chromosomal position on specific repair outcomes and partner choices. Also, utilizing a variety of genetic and cytological techniques, I will assess the roles of known meiotic proteins in promoting specific meiotic repair outcomes. Further, I will utilize two new reagents I generated to assess dynamics of the early stages of meiotic DSBR in live worms, establish the roles of meiotic chromosome structures in regulating DSB formation and repair, and determine a relationship between specific repair partner choices and classes of early DSBR stage dynamics. Overall, these studies will reveal how recombination pathway and partner preferences ensure that chromosomes form the connections necessary for chromosome segregation and repair DSBs for maintaining genomic integrity.

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），并确保在过程中正确的染色体分离 减数分裂，二倍体生物体产生单倍体配子的专门细胞分裂程序，例如 精子和卵子。重组事件的扰动可能会损害这些基本的细胞功能， 最终导致癌症、生育问题或出生缺陷。减数分裂重组是由 DSB 发起的， 使用有利于同源染色体利用的减数分裂特异性机制进行修复 （而不是姐妹染色单体）作为重组伙伴并促进交叉（而不是 非交叉）DSB 修复（DSBR）过程的结果。同源之间的交叉重组 染色体需要建立临时的物理连接，以促进正确的染色体 减数分裂期间的分离。为了促进这些重组途径和合作伙伴的偏好 为了在同源染色体之间产生交叉，生殖细胞需要专门的 DSBR 程序在减数分裂前期开始。在减数分裂前期晚期，减数分裂细胞经历 DSBR 要求中的第二个切换，建议恢复到典型的修复首选项的利用 有丝分裂细胞（例如，有利于姐妹染色单体作为修复伙伴）。这个建议的开关 可以在减数分裂之前修复任何剩余的 DSB，从而保持基因组完整性。 利用线虫实验系统，拟议的研究将解决不同的重组如何 减数分裂过程中采用途径和伙伴来促进同源物之间的交叉形成 并在减数分裂之前修复任何剩余的 DSB。评估时间和机械 这些途径和合作伙伴选择的特点，我将扩大我们最近发布的检测系统的范围 通过开发一种检测方法来检测和区分在特定条件下诱导的 DSB 的不同修复产物 地点。通过这种测定，我将直接测试减数分裂期间伴侣偏好的假设转变 前期进展并确定染色体位置对特定修复结果的影响以及 合作伙伴的选择。此外，利用各种遗传和细胞学技术，我将评估已知的作用 减数分裂蛋白促进特定减数分裂修复结果。此外，我将使用两种新试剂 生成用于评估活蠕虫减数分裂 DSBR 早期阶段的动态，建立减数分裂的作用 染色体结构调节 DSB 形成和修复，并确定特定之间的关系 修复合作伙伴的选择和早期 DSBR 阶段动态的类别。总的来说，这些研究将揭示如何 重组途径和伴侣偏好确保染色体形成必要的连接 染色体分离和修复 DSB 以维持基因组完整性。