Isolation and characterization of C.elegans meiotic mutants - regulation of chromosome association dynamics during meiosis

线虫减数分裂突变体的分离和表征 - 减数分裂过程中染色体关联动态的调节

• 批准号: 401960-2011
• 负责人: EgydiodeCarvalho, Carlos
• 金额: $ 2.55万
• 依托单位: University of Saskatchewan
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2016
• 资助国家: 加拿大
• 起止时间: 2016-01-01 至 2017-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=596029
• 关键词: Isolation; characterization; C.elegans; meiotic; mutants

The tight control of chromosome association and dissociation during cell division ensures the viability of daughter cells. In meiosis, chromosomes separate in two steps such that first homologs segregate in meiosis I and later sister chromatids disjoin in meiosis II. To avoid the sudden separation of sister chromatids already in meiosis I and subsequent collapse of cell division, cohesion proteins must not be completely removed from meiosis I chromosomes. Eukaryotic cells accomplish that by differentially protecting subsets of cohesion proteins on chromosomes from the activity of separase, an enzyme required to break chromosomal links. By selectively protecting cohesion proteins, meiotic cells can sustain sister chromatid association past homolog segregation. This protection of cohesion has been correlated with the presence of the centromere, the connecting point between sister chromatids and a center hub from where chromosomes attach to the spindle. However, a whole set of animal and plant species have cells whose chromosomes do not have a classic centromere. Nonetheless, protection of chromosome cohesion in these organisms still needs to occur.

细胞分裂过程中染色体结合和解离的严格控制确保了子细胞的活力。在减数分裂中，染色体分两步分离，首先同源染色体在减数分裂I中分离，随后姐妹染色单体在减数分裂II中分离。为了避免已经在减数分裂I中的姐妹染色单体的突然分离和随后的细胞分裂的崩溃，内聚蛋白不能从减数分裂I染色体上完全去除。真核细胞通过区别保护染色体上的内聚蛋白亚群免受分离酶（一种破坏染色体连接所需的酶）的活性的影响来实现这一点。通过选择性保护凝聚蛋白，减数分裂细胞可以维持姐妹染色单体联合过去同源分离。这种对凝聚力的保护与着丝粒的存在有关，着丝粒是姐妹染色单体之间的连接点和染色体附着到纺锤体的中心枢纽。然而，一整套动物和植物物种的细胞染色体不具有典型的着丝粒。尽管如此，这些生物体中的染色体凝聚力的保护仍然需要发生。