Enzymology Of Eukaryotic Mismatch Repair

真核错配修复的酶学

• 批准号: 8403580
• 负责人: PAUL LAWRENCE MODRICH
• 金额: $ 43.02万
• 依托单位: DUKE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-01 至 2014-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8403580
• 关键词: Accounting; Address; Apoptotic; Biochemical; Catalytic Domain; Cells; Cisplatin; Clinical; Collaborations; Colon Carcinoma; Complex; DNA; DNA Damage; DNA biosynthesis; DNA lesion; DNA-Protein Interaction; Defect; Development; Elements; Enzymatic Biochemistry; Event; Future; Genetic; Genetic Recombination; Human; Human Characteristics; Inherited; Laboratories; Lesion; Malignant Neoplasms; Mismatch Repair; Mitotic; Molecular; Mutation; Nature; Nerve Degeneration; Neurodegenerative Disorders; Neurons; Pathway interactions; Pharmaceutical Preparations; Phosphotransferases; Predisposition; Preparation; Process; Production; Proteins; Reaction; Repair Complex; Resistance; Role; Sequence Homologs; Set protein; Signal Transduction; Somatic Cell; Staging; Structure; Syndrome; System; Thioguanine; Work; antitumor drug; base; cancer therapy; cytotoxic; interest; intergenerational; prevent; public health relevance; repaired; response; transmission process; tumor

DESCRIPTION (provided by applicant): DNA mismatch repair is a key mutation avoidance pathway that is of clinical interest for several reasons. Inactivation of mismatch repair is the cause of a common form of hereditary colon cancer and has been implicated in the development of a subset of sporadic tumors. Mismatch repair defects also have implications for cancer therapy because inactivation of the pathway renders cells resistant to the cytotoxic effects of certain anti-tumor drugs, a consequence of participation of the system in the DNA damage response. Perhaps surprisingly, mismatch repair function is also required for the production of certain mutations, such as the expansion of (CAG)n repeat sequences, the primary cause of a number of neurodegenerative diseases. By elucidating the molecular nature of human mismatch repair, we hope to understand its roles in controlling the occurrence of mutation. To this end we propose four lines of work: (1) Available information on the nature of strand-directed human mismatch repair indicates that the course of the reaction is dictated by an evolving set of protein-protein and protein-DNA interactions, and that repair events initiated by the mismatch recognition activities MutS1 and MutS2 differ in significant ways. By analyzing the nature of selected multi-protein and multi-protein-DNA complexes, we hope to further clarify the mechanisms of MutS1- and MutS2-initiated repair events. (2) The somatic expansion stage of (CAG)n neurodegenerative diseases, which depends on the mismatch repair activities MutS2 and MutL1, can occur in postmitotic cells, suggesting involvement of repair DNA synthesis in this process. The nature of processing of (CAG)n repeat elements by the human mismatch repair system will be addressed in both extract and purified systems. (3) Mismatch repair function is required for checkpoint and apoptotic responses to SN1 DNA methylators. Using a biochemical approach, we will pursue the mechanisms of MutS1- and MutL1-dependent activation of the ATR damage-signaling kinase in response to O6-methylguanine, the primary cytotoxic lesion produced by this class of drug. (4) Collaborative studies with the laboratory of Lorena Beese will address the structural basis of lesion recognition and processing by the human mismatch recognition system.

描述（由申请人提供）：DNA错配修复是一个关键的突变避免途径，有几个原因引起临床兴趣。失活的错配修复是一种常见形式的遗传性结肠癌的原因，并已涉及到一个子集的散发性肿瘤的发展。错配修复缺陷也对癌症治疗有影响，因为该途径的失活使细胞抵抗某些抗肿瘤药物的细胞毒性作用，这是该系统参与DNA损伤反应的结果。也许令人惊讶的是，错配修复功能对于某些突变的产生也是必需的，例如（CAG）n重复序列的扩增，这是许多神经退行性疾病的主要原因。通过阐明人类错配修复的分子性质，我们希望了解其在控制突变发生中的作用。为此，我们提出了四方面的工作：(1)关于链导向的人类错配修复的性质的现有信息表明，反应的过程是由一组不断发展的蛋白质-蛋白质和蛋白质- dna相互作用决定的，由错配识别活动MutS1和MutS2发起的修复事件在很大程度上不同。通过分析所选择的多蛋白和多蛋白- dna复合物的性质，我们希望进一步阐明MutS1-和muts2启动修复事件的机制。(2)神经退行性疾病（CAG）的体细胞扩张阶段依赖于错配修复活性MutS2和MutL1，可发生在有丝分裂后细胞中，提示修复DNA合成参与了这一过程。人类错配修复系统处理（CAG）n重复元素的性质将在提取和纯化系统中得到解决。(3)错配修复功能是SN1 DNA甲基化反应的检查点和凋亡反应所必需的。使用生化方法，我们将探索ATR损伤信号激酶的MutS1-和mutl1依赖性激活对o6 -甲基鸟嘌呤的反应机制，o6 -甲基鸟嘌呤是这类药物产生的原发性细胞毒性损伤。(4)与Lorena Beese实验室合作研究人类失配识别系统对病变识别和处理的结构基础。