泛素交联酶UbcH7在DNA损伤应答过程中的功能和机制分析

项目名称： 泛素交联酶UbcH7在DNA损伤应答过程中的功能和机制分析

项目编号： No.31501150

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 生物科学

项目作者： 张雷

作者单位： 湖北工业大学

项目金额： 21万元

中文摘要： DNA 损伤应答对于维持细胞基因组稳定性至关重要，异常的DNA损伤应答和细胞癌变相关，并经常导致肿瘤细胞对放疗或化疗药物耐受。申请人前期工作表明，泛素交联酶UbcH7（Ube2L3）参与了抑癌蛋白53BP1的泛素化修饰及蛋白酶体途径降解，指导细胞采用同源重组的精细方式修复DNA双链断裂；UbcH7缺乏抑制53BP1的降解，使细胞选择易错方式修复DNA损伤，造成细胞对化疗和放疗药物敏感性增强，并最终导致高效的细胞死亡。本项目将依赖现有结果，利用shRNA筛选，蛋白质pull-down，DNA双链断裂修复分析等技术进一步阐述UbcH7在细胞DNA损伤应答中的功能机制；并以UbcH7为靶点，利用细胞生物学和生物化学等手段开发短肽类药物对抗细胞放化疗耐受。本研究将为肿瘤治疗提供一种更有加效地思路和方法。

中文关键词： DNA损伤应答；；UbcH7；泛素化；泛素交联酶；；DNA双链断裂修复

英文摘要： DNA damage response (DDR) plays a key role in genome stability maintenance, thereby providing an important target for anticancer therapy. Aberrant DNA damage response (DDR) is associated with tumorigenesis, resistance to chemotherapy and radiation treatment. In the presence of BRCA1 protein, cells are prone to perform homologous recombination (HR) to repair double-strand breaks(DSBs), while nonhomologous end-jointing (NHEJ) in G1-phase is used in the absence of BRCA1 or with enhanced 53BP1 retention. The latter manner usually leads to an increased sensitivity to anticancer therapies and cells death caused by impropriate genes arrangement. Our previous data showed that ubiquitin-conjugating enzyme H7 (UbcH7)-dependent ubiquitination and proteasome-dependent degradation are involved in the regulation of 53BP1 protein. Decreased UbcH7 level caused with RNAi or catalytically dead (C86S) mutant overexpression suppresses the degradation of 53BP1 and drives cells to perform nonhomologous end-jointing (NHEJ) repair, which bring about efficient cells death when treated with radiation or chemotherapy. Here, we would further investigate the function significance of UbcH7 in the process of DNA damage response based on our previous data. We would also identify the function region of UbcH7 protein and explore its potential role in short chain polypeptide medicine exploitation and clinical therapy. Based on the above, our results will provide more evidence for the role of UbcH7 and supply a new understanding for future anticancer therapy.

英文关键词： DNA damage response;UbcH7;Ubiquitination;ubiquitin-conjugating enzyme;DSB repair