Novel Interactions of DNA Repair Processes in Replication Fork Maintenance

复制叉维护中 DNA 修复过程的新相互作用

• 批准号: 8246242
• 负责人: Priscilla K. Cooper
• 金额: $ 40.76万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2012
• 资助国家: 美国
• 起止时间: 2012-01-01 至 2016-10-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8246242
• 关键词: Adult; Affect; Aging; Base Excision Repairs; Biochemical; Biological; Cancer Etiology; Cell Cycle; Cell Cycle Checkpoint; Cell Cycle Progression; Cell Survival; Cells; Cockayne Syndrome; Collaborations; Coupled; Cytogenetics; DNA Damage; DNA Double Strand Break; DNA Repair; DNA annealing; DNA biosynthesis; DNA repair protein; Defect; Development; Disease; Environment; Environmental Exposure; Exposure to; Face; Family; Filament; Genetic; Genetic Transcription; Genome; Genome Stability; Genomic Instability; Genomics; Goals; Human; Inherited; Laboratories; Lead; Lesion; Maintenance; Malignant Neoplasms; Maps; Mediating; Mediator of activation protein; Modeling; Molecular; Mutation; Nerve Degeneration; Nucleotide Excision Repair; Organism; Outcome; Pathway interactions; Phenotype; Predisposition; Premature aging syndrome; Process; Proteins; Regulation; Risk; Role; S Phase; Site; Source; Structure; System; Testing; Transcription-Coupled Repair; Werner Syndrome; Xeroderma Pigmentosum; age related; base; cancer cell; cancer therapy; developmental disease; disease phenotype; endonuclease; exodeoxyribonuclease; helicase; homologous recombination; human disease; insight; mutant; nervous system disorder; novel; novel strategies; oxidative DNA damage; postnatal; presynaptic; prevent; recombinase; recombinational repair; repaired; response

DESCRIPTION (provided by applicant): Cells must maintain the integrity of their genomes in order to propagate and survive. However, genomes are constantly challenged by damage from endogenous metabolites and environmental sources that pose impediments to replication and transcription. Special risks arise during replication. If the replication fork is not protected, replisome stalling at lesions can ultimately lead to strand breakage, loss of genetic information, and genomic instability. To face these challenges, organisms evolved multiple DNA repair and checkpoint pathways that must be coordinated with each other, as well as with DNA replication. Breakdown either in any of these processes or their coordination can corrupt genome integrity and cause human disease phenotypes ranging from aging to cancer. This proposal aims to understand the biochemical basis and biological significance of two unexpected findings. First, the DNA repair protein XPG is up-regulated in S-phase and localizes to foci containing proteins that repair damaged replication forks. Second, XPG interacts physically and functionally with WRN, which is known to be important for maintaining genomic integrity during S-phase, and also interacts directly with the RAD51 recombinase. The central hypothesis to be tested is that XPG has novel roles in replication fork maintenance both cooperatively with WRN and through facilitation of RAD51-mediated homologous recombination. The proposed approaches harness the complementary biochemical and cell biological expertise of two established laboratories and their collaborators. Aim 1 will define the role of XPG at replication forks and characterize the biological consequences of its loss. Aim 2 will test the hypothesis that during S-phase XPG functions with WRN at a subset of stalled replication forks and determine the conditions under which they interact in cells. Aim 3 will investigate a proposed role for XPG as a mediator of homologous recombinational repair of replication-associated DNA double-strand breaks. The proposed studies will define the molecular basis for interactions among the DNA repair processes mediated by XPG and WRN and their novel role in preventing loss of genomic integrity during S phase, with implications both for informed regulation of environmental exposures and rational development of novel cancer therapies. PUBLIC HEALTH RELEVANCE: The proposed studies will determine the mechanisms and biological significance of a recently discovered role for the multi-functional DNA repair protein XPG in replication fork maintenance. This novel function for XPG is mediated in part through direct interactions both with the RAD51 recombinase and with another multi-functional DNA repair protein WRN, both of which are important in preserving the integrity and stability of the genome. Mutations in XPG or WRN give rise to different inherited diseases that include cancer predisposition and aging phenotypes, while the RAD51 pathway is essential for cell viability. The project results will provide new insights into interactions among DNA repair systems, and how they protect humans from neurodegeneration, premature aging and cancer as a result of DNA damage from environmental and endogenous sources. The proposed studies will also help provide a rational basis for regulating environmental exposure to DNA damaging agents and for administering DNA damaging anti-cancer therapies.

描述（由申请人提供）：细胞必须保持其基因组的完整性才能繁殖和生存。然而，基因组不断受到内源代谢物和环境来源损害的挑战，这些损害对复制和转录构成障碍。复制过程中会出现特殊风险。如果复制叉不受保护，复制体在损伤处停滞最终会导致链断裂、遗传信息丢失和基因组不稳定。为了应对这些挑战，生物体进化出了多种 DNA 修复和检查点途径，这些途径必须相互协调，并与 DNA 复制协调。这些过程中的任何一个或其协调的破坏都会破坏基因组的完整性，并导致从衰老到癌症等人类疾病表型。 该提案旨在了解两个意外发现的生化基础和生物学意义。 首先，DNA 修复蛋白 XPG 在 S 期上调，并定位于含有修复受损复制叉的蛋白质的病灶。其次，XPG 在物理和功能上与 WRN 相互作用，已知 WRN 对于维持 S 期基因组完整性非常重要，并且还直接与 RAD51 重组酶相互作用。要测试的中心假设是 XPG 与 WRN 合作并通过促进 RAD51 介导的同源重组在复制叉维持中具有新的作用。拟议的方法利用了两个已建立的实验室及其合作者的互补生化和细胞生物学专业知识。目标 1 将定义 XPG 在复制叉中的作用并描述其丢失的生物学后果。目标 2 将测试以下假设：在 S 期 XPG 与 WRN 在停滞的复制叉子集上发挥作用，并确定它们在细胞中相互作用的条件。 目标 3 将研究 XPG 作为复制相关 DNA 双链断裂同源重组修复介质的作用。拟议的研究将确定 XPG 和 WRN 介导的 DNA 修复过程之间相互作用的分子基础，及其在防止 S 期基因组完整性丧失方面的新作用，对环境暴露的知情调节和新型癌症疗法的合理开发都有影响。 公共健康相关性：拟议的研究将确定最近发现的多功能 DNA 修复蛋白 XPG 在复制叉维持中的作用的机制和生物学意义。 XPG 的这一新功能部分是通过与 RAD51 重组酶和另一种多功能 DNA 修复蛋白 WRN 的直接相互作用来介导的，这两者对于保持基因组的完整性和稳定性都很重要。 XPG 或 WRN 的突变会引起不同的遗传性疾病，包括癌症易感性和衰老表型，而 RAD51 通路对于细胞活力至关重要。该项目的结果将为 DNA 修复系统之间的相互作用以及它们如何保护人类免受因环境和内源性 DNA 损伤而导致的神经退行性变、过早衰老和癌症提供新的见解。拟议的研究还将有助于为调节 DNA 损伤剂的环境暴露和实施 DNA 损伤抗癌疗法提供合理的基础。