Biological Role of XPG DNA Repair Protein Interactions with WRN and BLM Helicases

XPG DNA 修复蛋白与 WRN 和 BLM 解旋酶相互作用的生物学作用

• 批准号: 7547754
• 负责人: Kelly S Trego
• 金额: $ 3.26万
• 依托单位: UNIVERSITY OF CALIF-LAWRENC BERKELEY LAB
• 依托单位国家: 美国
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-12-18 至 2009-06-25
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7547754
• 关键词: Affect; Aging; Base Excision Repairs; Biological; Bloom Syndrome; Cell Cycle; Cell Fractionation; Cell physiology; Cells; Chemicals; Cockayne Syndrome; Complex; DNA; DNA Damage; DNA Repair Pathway; DNA biosynthesis; DNA repair protein; Data; Detection; Disease; Excision; Failure; Family member; Genetic Recombination; Genetic Transcription; Genome Stability; Genomic Instability; Genomics; Human; Immunofluorescence Immunologic; Immunoprecipitation; Incidence; Ionizing radiation; Lead; Lesion; Link; Maintenance; Malignant Neoplasms; Metabolism; Modeling; Mutation; Neurologic; Play; Premature aging syndrome; Process; Proteins; Role; Site; Source; Symptoms; Testing; Transcription-Coupled Repair; Werner Syndrome; cell injury; developmental disease; helicase; homologous recombination; insight; novel; oxidative damage; prevent; recombinational repair; repaired; telomere

DESCRIPTION (provided by applicant): Genomic integrity is persistently threatened by endogenous damage from the cellular metabolism and exogenous environmental sources including UV, ionizing radiation, and mutagenic chemicals. To counter this damage, cells have evolved complex and interconnected DNA repair pathways to coordinate lesion detection and removal with other vital cellular processes such as DNA replication, transcription and recombination. Failure in any link can lead to genomic instability, a known precursor to both cancer and aging. The broad focus of this proposal is to understand the biological significance of the interaction between three proteins involved in preventing genomic instability: XPG, and the human RecQ family members BLM and WRN. XPG has important non-enzymatic functions in both transcription-coupled repair and in base-excision repair (BER) of oxidative damage, and mutations that block functions of XPG lead to a severe neurological and developmental disorder with symptoms of premature aging, Cockayne syndrome (XP-G/CS). Further, WRN and BLM both play important roles in the maintenance of genomic integrity during replication. The loss of BLM leads to Bloom's syndrome, characterized by a high incidence of cancer, and the loss of WRN leads to Werner's syndrome, a premature aging disorder with increased cancer incidence. Preliminary data suggests a novel replication-associated role for XPG. The hypotheses to be tested are that XPG functions with WRN or BLM in homologous recombination repair (HRR) of stalled or collapsed replication forks after DNA damage, and/or during normal telomere replication. Aim 1 will use model DNA substrates of HRR intermediates to investigate the mechanisms by which XPG affects the function of BLM and WRN enzymatic activities. Aim 2 will use immunofluorescence, cell fractionation, and immunoprecipitations to test the hypothesis that XPG localizes to sites of stalled or collapsed replication forks with WRN or BLM. Aim 3 will examine primary XP-G/CS cells for telomere integrity, and determine the cell cycle and DNA damage-induced conditions under which XPG localizes to the telomeres. These studies will provide valuable insights into the roles of highly multifunctional proteins to regulate crosstalk between DNA replication and repair. Both of these DNA transactions are critically important in the maintenance of genomic stability and defense against cancer and aging.

描述（由申请人提供）：基因组完整性持续受到来自细胞代谢的内源性损伤和外源性环境来源的威胁，包括紫外线、电离辐射和致突变化学物质。为了对抗这种损伤，细胞已经进化出复杂且相互关联的DNA修复途径，以协调损伤的检测和清除与其他重要的细胞过程，如DNA复制、转录和重组。任何一个环节的失败都会导致基因组不稳定，这是已知的癌症和衰老的前兆。该提案的广泛焦点是了解参与预防基因组不稳定的三种蛋白质之间相互作用的生物学意义：XPG，以及人类RecQ家族成员BLM和WRN。XPG在氧化损伤的转录偶联修复和碱基切除修复（BER）中都具有重要的非酶功能，阻断XPG功能的突变可导致严重的神经和发育障碍，并伴有早衰症状，即Cockayne综合征（XP-G/CS）。此外，WRN和BLM都在复制过程中维持基因组完整性方面发挥重要作用。BLM的缺失导致Bloom's综合征，其特征是癌症的高发病率，而WRN的缺失导致Werner's综合征，这是一种癌症发病率增加的早衰疾病。初步数据表明XPG具有一种新的与复制相关的作用。待验证的假设是，XPG与WRN或BLM一起在DNA损伤后和/或正常端粒复制过程中对停滞或崩溃的复制叉进行同源重组修复（HRR）。目的1将使用HRR中间体的模型DNA底物来研究XPG影响BLM和WRN酶活性功能的机制。目的2将使用免疫荧光、细胞分离和免疫沉淀来验证XPG定位于具有WRN或BLM的停滞或崩溃复制叉的位点的假设。目的3将检测原代XP-G/CS细胞的端粒完整性，并确定XPG定位于端粒的细胞周期和DNA损伤诱导条件。这些研究将为高度多功能蛋白在调节DNA复制和修复之间的串扰中的作用提供有价值的见解。这两种DNA交易在维持基因组稳定性和抵御癌症和衰老方面都至关重要。