The role of hMLH1-hMRE11 in DNA mismatch repair

hMLH1-hMRE11在DNA错配修复中的作用

基本信息

批准号：
7211389
负责人：
CHENGTAO HER
金额：
$ 22.28万
依托单位：
WASHINGTON STATE UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2004
资助国家：
美国
起止时间：
2004-04-15 至 2009-03-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/7211389
关键词：
Address Affect Binding Biological Biological Assay Cell Cycle Regulation Cells Chromosome Segregation Classification Complex DNA DNA Damage DNA Double Strand Break DNA Mismatch Repair Protein MLH1 DNA Repair DNA biosynthesis DNA chemical synthesis Defect Depth Development Disease Disruption Dominant-Negative Mutation Event Excision Exonuclease Generations Genes Genetic Genetic Recombination Genome Stability Germ-Line Mutation Goals Hela Cells Hereditary Nonpolyposis Colorectal Neoplasms Homologous Gene Human In Vitro Link MLH1 gene Malignant Neoplasms Mediating Medical Surveillance Meiotic Recombination Microsatellite Instability Mismatch Repair Missense Mutation Molecular Monitor Mutation NBS1 gene Nuclear Nucleotides Numbers Pathogenesis Pathway interactions Pattern Personal Satisfaction Play Process Prognostic Marker Proteins Rate Research Research Personnel Role Series Signal Transduction Site Small Interfering RNA Solid System Telomere Maintenance Testing Therapeutic Intervention Work base design endonuclease human MLH1 protein human disease in vivo insight mismatch repair protein 1 novel diagnostics nuclease programs reconstitution repaired response

项目摘要

DESCRIPTION (provided by applicant): Cellular surveillance for the integrity of genetic information passed from parental cells to subsequent generations is carried out by a network of proteins primarily involved in cell-cycle regulation, DNA replication, DNA repair, and chromosome segregation. Defects of any protein factor in this network render cells to genetic instability to different extents, and therefore, predispose to cancer. One of the involved pathways is the DNA mismatch repair (MMR) system that has a crucial role in maintaining genome stability by monitoring and correcting mismatched nucleotides occurred during DNA recombination and DNA synthesis. Mutations in MMR genes can cause higher mutation rates and increase microsatellite instability. Germline mutations in several MMR genes, including MutS and MutL homologues, contribute to the pathogenesis of hereditary nonpolyposis colorectal cancer (HNPCC) in humans, with mutations in hMLH1 and hMSH2 genes representing major contributors to HNPCC. Our recent work has revealed a direct physical link between hMLH1 and hMRE11 both in vitro and in vivo. Human hMRE11 represents an essential nuclease of the multifunctional protein complex (hRAD50-hMRE11-NBS1) that promotes repair of DNA double-strand breaks and plays a role in the signaling of DNA damage response as well as in meiotic recombination and telomere maintenance. Mutations in hMRE11 contribute to the development of the rare "AT-like" (ATLD) disorder. It is known that hMRE11-associated complex displays dynamic spatial and temporal cellular distribution and form DNA-damage induced foci at the sites of DNA damage. Therefore, the long-term goal of this research program is to elucidate the molecular mechanisms involved in MMR and the functional links between MMR proteins and the hMRE11-associated protein complex, as well as the biological effects of mutations that disrupt the interplay among these protein factors. We propose to address these important issues through a vigorous systematic approach that includes the following specific aims: (1) to test the hypothesis that hMRE11 represents a functional component of the DNA mismatch repair pathway; (2) to determine whether hMLH1 binding stimulates nuclease activities of hMRE11 and the functional roles of hMRE11 nuclease activities in the process of MMR; (3) to test the hypothesis that hMLH1 HNPCC missense mutations differentially affect the formation of hMLHI-hMRE11 and hMLHI-hPMS2 heterocomplexes, and therefore disruption of hMLH1-hMRE11 complex represents an alternative mechanism underlying the pathogenic effects of hMLH1 HNPCC mutations. The results of the proposed studies will provide insight into the molecular mechanisms by which MMR and the hMREll-associated complex act together to maintain genetic stability, as well as to provide a better understanding of hMLH1 and/or hMRE11 deficiencies in human diseases such as cancer.

描述（由申请人提供）：对从亲本细胞传递给后代的遗传信息的完整性进行细胞监视是通过主要涉及细胞周期调节、DNA 复制、DNA 修复和染色体分离的蛋白质网络进行的。该网络中任何蛋白质因子的缺陷都会使细胞在不同程度上产生遗传不稳定，因此容易患癌症。其中涉及的途径之一是DNA错配修复（MMR）系统，该系统通过监测和纠正DNA重组和DNA合成过程中发生的错配核苷酸，在维持基因组稳定性方面发挥着至关重要的作用。 MMR 基因突变会导致更高的突变率并增加微卫星的不稳定性。包括 MutS 和 MutL 同源物在内的多个 MMR 基因的种系突变导致人类遗传性非息肉病性结直肠癌 (HNPCC) 的发病机制，其中 hMLH1 和 hMSH2 基因的突变是 HNPCC 的主要贡献者。我们最近的工作揭示了 hMLH1 和 hMRE11 在体外和体内的直接物理联系。人 hMRE11 是多功能蛋白质复合物 (hRAD50-hMRE11-NBS1) 的必需核酸酶，可促进 DNA 双链断裂的修复，并在 DNA 损伤反应信号传导以及减数分裂重组和端粒维持中发挥作用。 hMRE11 突变会导致罕见的“AT 样”(ATLD) 疾病的发生。众所周知，hMRE11 相关复合物表现出动态的空间和时间细胞分布，并在 DNA 损伤部位形成 DNA 损伤诱导的病灶。因此，该研究计划的长期目标是阐明MMR涉及的分子机制以及MMR蛋白与hMRE11相关蛋白复合物之间的功能联系，以及破坏这些蛋白之间相互作用的突变的生物学效应。因素。我们建议通过强有力的系统方法来解决这些重要问题，其中包括以下具体目标：（1）检验 hMRE11 代表 DNA 错配修复途径的功能组成部分的假设； (2)确定hMLH1结合是否刺激hMRE11核酸酶活性以及hMRE11核酸酶活性在错配修复过程中的功能作用； (3)检验hMLH1 HNPCC错义突变对hMLHI-hMRE11和hMLHI-hPMS2异质复合物的形成有不同影响的假设，因此hMLH1-hMRE11复合物的破坏代表了hMLH1 HNPCC突变致病作用的另一种机制。拟议研究的结果将深入了解 MMR 和 hMREll 相关复合物共同作用以维持遗传稳定性的分子机制，并更好地了解癌症等人类疾病中的 hMLH1 和/或 hMRE11 缺陷。