酿酒酵母姐妹染色单体黏连与DNA复制的偶联机制

Sister chromatid cohesion (SCC) is a vital cellular process that connects the products of DNA replication in S phase till their correct separation during anaphase. Meanwhile, SCC also serves important roles in DNA repair, dynamic chromatin structure and gene regulation. It has been suggested that SCC is closely linked to DNA replication. But the coupling mechanism remains unclear. We screened some possible SCC regulators by techniques including high throughput gene-gene or protein-protein interactions in Saccharomyces cerevisiae. One of them is Rtt101-Mms1-Mms22, a Cul4-family E3 ubiquitin ligase. In this project, we will use a combination of molecular genetics, cell biology and biochemical techniques to study the mechanism of how Rtt101-Mms1-Mms22 and other possible new factors control the SCC establishment during S phase.The research will focus on the effect of Rtt101-Mms1-Mms22 on cohesin acetyltransferase Eco1 and the effect of replication-coupled nucleosome assembly (RCNA) on SCC. This research will not only shed new light on the coupling mechanism of DNA replication and SCC, but also increase our knowledge in how Rtt101-Mms1-Mms22 may participate in DNA damage repair.

姐妹染色单体黏连（SCC）衔接着染色质复制和分离两大核心事件，是复制的染色体正确分离的前提。SCC还参与DNA修复、染色质高级结构、基因表达调控等过程。研究表明SCC的建立依赖并伴随于DNA复制进程，但具体的偶联机制仍不明确。我们前期在酿酒酵母中通过高通量遗传互作筛选到了几个可能参与SCC调控的新因子，包括泛素连接酶Rtt101-Mms1-Mms22。本项目拟综合利用遗传、生化以及细胞生物学等手段对Rtt101-Mms1-Mms22调控SCC的机制进行深入研究。内容主要包括Rtt101-Mms1-Mms22对乙酰转移酶Eco1的影响；Rtt101-Mms1-Mms22参与的复制偶联的核小体组装（RCNA）途径对姐妹染色单体黏连的调控作用等。这些研究不仅为DNA复制与SCC的偶联机制提供有价值的线索，还有助于揭示Rtt101-Mms1-Mms22参与DNA损伤修复可能的新机制。

姐妹染色单体黏连（SCC）是染色体正确分离的前提。SCC还参与DNA修复、基因的转录调控等过程。本项目以酿酒酵母和人293T细胞为材料，利用遗传、生化以及细胞生物学等手段对调控SCC的机制进行了深入研究。结果表明，在酿酒酵母和高等哺乳动物中存在着保守的调控机制，Rtt101-Mms1-Mms22泛素连接酶（人细胞中Cul4-Ddb1-Mms22L）和PCNA协同作用于乙酰转移酶Eco1（人细胞中Esco2）,在染色体上将黏连蛋白的亚基Smc3乙酰化, 促进姐妹染色单体黏连建立。我们还发现Rtt101-Mms1-Mms22在DNA复制过程中偶联核小体组装和姐妹染色单体黏连。这些研究不仅为解答DNA复制与SCC的偶联机制提供了有价值的线索，还有助于揭示Rtt101-Mms1-Mms22参与DNA损伤修复的分子机制。