Ago2磷酸化在DNA损伤修复中的功能分析

项目名称： Ago2磷酸化在DNA损伤修复中的功能分析

项目编号： No.31401202

项目类型： 青年科学基金项目

立项/批准年度： 2015

项目学科： 遗传学与生物信息学、细胞生物学

项目作者： 李艳

作者单位： 清华大学

项目金额： 10万元

中文摘要： 申请人所在实验室发现一类产生于DNA双链断裂（double strand break, DSB）位点附近序列并在DSB修复中起重要作用的新的小RNA，diRNA。diRNA和Ago2组成的复合体促进DSB修复蛋白Rad51被招募到DSB位点，从而促进DSB修复以同源重组的方式完成。磷酸化是调节众多已知参与DNA损伤应答的蛋白活性的重要方式。我们前期研究发现，DNA损伤可特异性地在Ago2上的5个位点诱导产生磷酸化修饰，并且这些磷酸化位点的突变严重影响DSB修复效率。本项目将在此发现的基础上，进一步探索Ago2磷酸化在DSB修复中的作用机理。我们将研究：1）磷酸化在Ago2结合diRNA 和Rad51以及DSB位点招募Rad51的作用；2）Ago2磷酸化是否受细胞周期调控；3）鉴定参与Ago2磷酸化的激酶。本项目研究结果对于阐明Ago2和diRNA在DSB修复中的功能及其作用机理有重要意义。

中文关键词： Ago2；DNA损伤诱导产生的小RNA；DNA修复；磷酸化；小RNA

英文摘要： Our lab previously found a novel type of small RNAs produced from the sequences in the vicinity of DNA double-strand break (DSB) sites in human cells. They are referred to as diRNAs for DSB-induced small RNAs. Ago2 binds to diRNAs and recruit diRNAs to DSB sites. The recruitment of Rad51, a protein assisting in DSB repair by homologous recombination (HR), requires the formation of Ago2/diRNA complex. Phosphorylation is an important way to regulate the activities of proteins involved in DNA damage response. We identified five sites that can be specifically phosphorylated in response to DSB in human Ago2. The mutations of these sites lead to reduced HR efficiency, suggesting that these phosphorylation events play key roles in DNA damage repair. Our study aims at: 1) determine whether the mutations of these phosphorylation sites affect the binding between Ago2 and diRNAs, the binding between Ago2 and Rad51, the recruitment of Rad51 to DSB sites; 2) explore the cell cyle regulation of Ago2 phosphorylation; 3) identify kinases responsible for Ago2 phosphorylation. Our study will provide significant new insights into the regulatory mechanisms for Ago2 and diRNA functions in DSB repair.

英文关键词： Ago2；diRNA；DNA repair；phosphorylation；small RNA