染色体分离调控是细胞周期调控领域一个根本性的重要问题，因为粘连蛋白的动态迁移以及染色体分离发生错误是婴儿出生缺陷和胚胎死亡的重要原因。粘连蛋白在染色体上的动态迁移涉及到其环形结构的打开与关闭。粘连蛋白的调控蛋白Wapl和Pds5能够将其从染色体上解离下来,但其分子机理还不清楚。申请人前期通过解析人源Wapl以及Pds5结合Wapl小肽的复合物结构，基于结构的生化细胞研究，对Wapl和Pds5如何打开粘连蛋白DNA出口的分子机制做了一定的探索。我们的结果显示，Wapl通过一个保守的YSR结构模式与sororin竞争结合Pds5，从而促使粘连蛋白从染色体上解离下来；Pds5结合Scc1的N端抑制了DNA出口的重新关闭。.基于前期的研究结果，以及近期建立的实验体系, 申请人将采用生物化学，细胞生物学，X射线晶体学以及冷冻电镜结合的方法更深入的研究染色体分离调控这一关键问题。

Regulation of chromosome segregation is very critical in cell cycle regulation as errors in cohesin dynamics and chromosome segregation are major causes for birth defect and embryonic lethality. Cohesin dynamics on chromosome involves opening and closing of its ring structure. Cohesin regulators, Wapl and Pds5, dissociate cohesin from chromosome, but the detailed mechanism is still unclear. I have previously solved the structures of human Wapl and human Pds5 bound to a Wapl peptide, uncovered the molecular mechanism of how these regulators open the DNA exit gate of cohesin using the structure-based biochemical and cellular biology methods. Our results show that Wapl competes with Sororin for Pds5 binding through the conserved YSR motif, promoting the dissociation of cohesin from chromosome; Pds5 binds to Scc1 N-terminal thus inhibits the re-closure of the DNA exit gate of cohesin..Based on our previous discoveries and assays we established recently, we will further explore the critical question using a combination of biochemical, cellular biology, X-ray crystallography and cryo-EM methods.