Mre11/Rad50/Nbs1 Structural Biology for DNA Damage Responses

Mre11/Rad50/Nbs1 DNA 损伤反应的结构生物学

• 批准号: 8068893
• 负责人: John A. Tainer
• 金额: $ 35.51万
• 依托单位: SCRIPPS RESEARCH INSTITUTE, THE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-08-01 至 2015-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8068893
• 关键词: ATP phosphohydrolase; Antibodies; Archaea; Architecture; Ataxia Telangiectasia; Ataxia-Telangiectasia-Mutated protein kinase; Binding; Biochemical; Cells; Cellular biology; Chemotherapy-Oncologic Procedure; Chromosomal Instability; Complex; DNA; DNA Binding; DNA Damage; DNA Double Strand Break; DNA Repair; Defect; Development; Disease; Eukaryota; Excision; Family; Fission Yeast; Foundations; Genetic; Genetic Polymorphism; Goals; Growth; Homologous Gene; Human; Immunodeficiency and Cancer; Intervention; Ionizing radiation; Knowledge; Link; Malignant Neoplasms; Meiosis; Molecular; Molecular Conformation; Mutation; Nijmegen Breakage Syndrome; Nucleotides; Outcome; Pathway interactions; Patients; Phenotype; Phosphoserine; Phosphothreonine; Phosphotransferases; Play; Predisposition; Process; Proteins; Radiation Tolerance; Radiation therapy; Research; Resistance; Resolution; Roentgen Rays; Role; Signal Transduction; Solutions; Specificity; Structural Biochemistry; Structure; Structure-Activity Relationship; Synchrotrons; Tail; Techniques; Technology; Telomere Maintenance; Testing; Walkers; Work; Yeasts; anticancer research; ataxia telangiectasia mutated protein; base; cancer radiation therapy; design; dimer; functional hypothalamic amenorrhea; genetic regulatory protein; homologous recombination; human CHEK1 protein; human disease; inhibitor/antagonist; insight; member; mutant; novel strategies; nuclease; protein complex; public health relevance; recombinational repair; repaired; resistance factors; response; structural biology; tumorigenesis

DESCRIPTION (provided by applicant): Cancer predispositions in humans and severe DNA damage phenotypes in yeast result from defects in the Mre11-Rad50-Nbs1 (MRN) complex. MRN plays central and essential roles in repairing DNA double-strand breaks (DSBs) during homologous recombination repair as well as acting in meiosis, antibody hypermutation, telomere maintenance, and DNA damage signaling through ATM kinase. Yet, detailed mechanistic insights into these diverse MRN functions remain limited. The Mre11 nuclease complex with the Rad50 ATPase is conserved from archaea to humans and is regulated by Nbs1 in S. pombe and humans. We propose three Specific Aims to advance knowledge of MRN structural biochemistry, conformations, and interactions relevant to DNA damage repair and signaling functions. To accomplish these Aims, we will apply advanced biophysical techniques, including synchrotron solution X-ray scattering and atomic resolution crystal structure technologies in concert with genetic and mutational analyses in yeast. The proposed integrated biophysical and genetic studies will test hypotheses regarding Mre11's role in DNA target specificity and processing, Rad50's role in ATP-induced conformational controls and architectural interactions, and Nbs1's role in modulating Mre11 and Rad50 activities. The expected results will characterize functionally key Mre11, Rad50 and Nbs1 protein-protein and protein-DNA interfaces, conformations, and interaction architectures. Furthermore, the DNA damage sensitivity observed in the absence of any one member of the MRN complex suggests that our results will form a platform to test the utility of inhibitors that increase cellular sensitivity to ionizing radiation and other DNA damaging agents used for cancer radiotherapy and chemotherapy. Overall the results will connect MRN to cellular outcomes and human disease by defining interactions and mechanisms controlling genetic integrity, cancer resistance, radiotherapy resistance, and predispositions to cancer. PUBLIC HEALTH RELEVANCE: Major goals for cancer research for the past decade have been the identification of the molecular underpinnings of cancer and the development of novel approaches to intervention. A major advance has been the characterization of the Mre11-Rad50-Nbs1 (MRN) complex as a critical suppressor of tumorigenesis and a resistance factor for current therapies. The proposed research will provide insights into the molecular mechanisms for MRN functions relevant to both cancer avoidance and interventions.

描述（由申请人提供）：人类的癌症倾向和酵母的严重 DNA 损伤表型是由 Mre11-Rad50-Nbs1 (MRN) 复合物的缺陷引起的。 MRN 在同源重组修复过程中修复 DNA 双链断裂 (DSB) 以及在减数分裂、抗体超突变、端粒维持和通过 ATM 激酶的 DNA 损伤信号传导中发挥着核心和重要作用。然而，对这些不同 MRN 功能的详细机制了解仍然有限。 Mre11 核酸酶与 Rad50 ATP 酶的复合物从古细菌到人类都是保守的，并且在粟酒裂殖酵母和人类中受 Nbs1 调节。我们提出了三个具体目标，以增进对 MRN 结构生物化学、构象以及与 DNA 损伤修复和信号传导功能相关的相互作用的了解。为了实现这些目标，我们将应用先进的生物物理技术，包括同步加速器溶液 X 射线散射和原子分辨率晶体结构技术，以及酵母的遗传和突变分析。拟议的综合生物物理和遗传学研究将测试有关 Mre11 在 DNA 靶标特异性和加工中的作用、Rad50 在 ATP 诱导的构象控制和结构相互作用中的作用以及 Nbs1 在调节 Mre11 和 Rad50 活性中的作用的假设。预期结果将表征关键功能 Mre11、Rad50 和 Nbs1 蛋白质-蛋白质和蛋白质-DNA 界面、构象和相互作用架构。此外，在 MRN 复合体任何一个成员都不存在的情况下观察到的 DNA 损伤敏感性表明，我们的结果将形成一个平台来测试抑制剂的效用，这些抑制剂可提高细胞对电离辐射和用于癌症放疗和化疗的其他 DNA 损伤剂的敏感性。总体而言，研究结果将通过定义控制遗传完整性、癌症抵抗力、放射治疗抵抗力和癌症易感性的相互作用和机制，将 MRN 与细胞结果和人类疾病联系起来。 公共健康相关性：过去十年癌症研究的主要目标是确定癌症的分子基础和开发新的干预方法。一项重大进展是将 Mre11-Rad50-Nbs1 (MRN) 复合物描述为肿瘤发生的关键抑制剂和当前疗法的耐药因子。拟议的研究将深入了解与癌症避免和干预相关的 MRN 功能的分子机制。