Enzymology Of Eukaryotic Mismatch Repair

真核错配修复的酶学

• 批准号: 7336327
• 负责人: PAUL LAWRENCE MODRICH
• 金额: $ 41.1万
• 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 2010-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7336327
• 关键词: Accounting; Address; Adenine Nucleotides; Biochemical; Biochemical Genetics; Cells; Cisplatin; Clinical; Colon Carcinoma; Complex; DNA; DNA Binding; DNA Damage; DNA Repair; DNA lesion; DNA-Binding Proteins; DNA-Directed DNA Polymerase; Defect; Development; Ensure; Enzymatic Biochemistry; Excision; Exodeoxyribonuclease I; Genes; Genetic; Genetic Recombination; Goals; HMGB1 gene; Human; In Vitro; Inherited; Laboratories; Lesion; MLH1 gene; MSH2 gene; Mammalian Cell; Mammals; Mediating; Mismatch Repair; Molecular; Molecular Conformation; Mutation; Nature; Nuclear Extract; PCNA gene; Pathway interactions; Pharmaceutical Preparations; Phosphotransferases; Play; Preparation; Process; Proteins; Reaction; Replication Error; Resistance; Roentgen Rays; Role; SS DNA BP; Signal Transduction; Solutions; Structure; System; Thioguanine; Time; Tissues; Yeasts; antitumor drug; base; cancer therapy; cytotoxic; interest; novel; reconstitution; research study; response; stoichiometry; tumor; yeast two hybrid system

Mismatch repair is a major contributor to genetic stability. This pathway is of clinical interest because mutations in mismatch repair genes are the cause of one of the most prevalent forms of hereditary colon cancer, and have been implicated in the development of a subset (¿ 15%) of sporadic tumors that can occur in a variety of tissues. Mismatch repair defects also have implications for cancer treatment because inactivation of the pathway renders cells resistant to the cytotoxic effects of certain anti-tumor drugs. The primary goals of this project are to elucidate the molecular nature of this DNA repair system as it functions in replication error correction and in the cellular response to DNA damage. Our aims are four-fold: (1) Nine activities (MutSa, MutS(3, MutLa, Exol, RFC, PCNA, RPA, HMGB1, and DNA polymerase 6) have been implicated in eukaryotic mismatch repair, but it is clear that additional, and as yet unknown, components play important regulatory roles in the reaction. We intend to isolate these activities and establish their functions in the reaction. (2) We have shown that subsets of the known human mismatch repair activities catalyze several partial reactions that account at least in part for the complexity of the overall reaction. We plan further characterization of the corresponding multi-protein¿DNA assemblies with respect to molecular activities, stoichiometry, and conformation, as well as modulatory effects of adenine nucleotides on these parameters. (3) The structural basis of mismatch/DNA lesion recognition and processing by the human mismatch repair system will be addressed in collaborative X-ray crystallographic studies with Lorena Beese's laboratory. (4) MutSa and MutLa defects render mammalian cells resistant to the cytotoxic effects of SN1 DNA methylators, 6-thioguanine, and cisplatin. In an attempt to clarify the function of the human mismatch repair system in the DNA damage response, we will pursue in vitro experiments with the hope of elucidating the mechanism of MutSa- and MutLa-dependent activation of the ATR damage-signaling kinase in response to O6-methylguanine lesions.

错配修复是遗传稳定性的主要因素。这种途径具有临床意义，因为