CDK1/Cyclin B1调控分离酶的机制及其对卵子染色体稳定的影响

卵细胞减数分裂中的染色体分离异常导致的染色体不稳定已经成为了不育、流产、先天性出生缺陷，以及辅助生殖失败等的首要原因。分离酶是染色体分离的执行者。实现染色体的正常分离和稳定需要通过，1、安全素抑制性结合；2、CDK1/Cyclin B1对分离酶抑制性磷酸化，对分离酶进行严格的调控。新的研究结果提示，CDK1/Cyclin B1对分离酶进行抑制性磷酸化的同时还进行Cyclin B1抑制性结合。本课题拟通过建立卵细胞特异性CDK1 T14Y15-A14F15突变和Cyclin B1敲除小鼠，结合安全素敲除小鼠，研究:1、减数分裂过程中CDK1/Cyclin B1抑制性磷酸化和结合分离酶的机制；2、卵细胞减数分裂过程中分离酶调节部分或完全缺失对卵子染色体分离和稳定的影响；3、染色体分离异常激活纺锤体检测点的机制。从而了解分离酶调节对卵细胞染色体分离和稳定的生物学意义及其对胚胎早期发生的影响。

Chromosome instability from chromosome mis-segregation during meiosis of the oocytes is considered as the leading cause of infertility, miscarriage, congenital birth defects, assisted reproductive failure, etc. Therefore, appropriate regulation of Separase, the executor of chromosome segregation, is critical. Separase is strictly controlled by dual mechanisms: Securin inhibitory binding, and CDK1/Cyclin B1 inhibitory phosphorylation. Recent results from Separase phospho-site point mutation mice and in vitro test suggested, besides inhibitory phosphorylation, CDK1/Cyclin B1 directly bind with Separase as well. By generating oocyte specific CDK1 inhibitory phospho-site point mutation (T14Y15-A14F15) and Cyclin B1 knockout mouse models, combined using established Securin knockout mouse model, we propose here to study, 1. The mechanisms of inhibitory phosphorylation and inhibitory binding with Separase by CDK1/Cyclin B1 during meiosis; 2. The chromosome instability from meiotic mis-segregation resulted from loss control of Separase. 3. The abnormal spindle checkpoint activation caused by abnormal meiotic chromosome segregation. This study will tell the biological significance of Separase regulation in chromosome segregation and chromosome stability of oocytes, and reveal the effects of chromosome instability on early embryogenesis.