Mechanisms of Error Prone Repair of DNA Breaks

DNA 断裂的易错修复机制

• 批准号: 8691535
• 负责人: SANG EUN LEE
• 金额: $ 8.79万
• 依托单位: UNIVERSITY OF TEXAS HLTH SCIENCE CENTER
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-01 至 2014-05-06
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8691535
• 关键词: Aging; Biochemical; Biochemistry; Biological; Biological Assay; Biological Process; Cells; Chromosomal Rearrangement; Chromosomal Stability; Clinical; Complex; DNA; DNA Damage; DNA Repair; DNA biosynthesis; DNA lesion; Direct Repeats; Disease Progression; Ensure; Enzymes; Eukaryota; Excision; Funding; Gene Conversion; Gene Targeting; Genes; Genetic; Genetic Recombination; Genetic Variation; Glean; Goals; Health; Human; Human Genetics; Kinetics; Light; Maintenance; Malignant Neoplasms; Maps; Microarray Analysis; Molecular; Molecular Biology; Monitor; Mutation; Pharmaceutical Preparations; Play; Premature aging syndrome; Prevention; Process; Property; Proteins; Public Health; Radiation; Reaction; Role; Sequence Deletion; Site; Source; Structure; Structure-Activity Relationship; Surgical Flaps; Tandem Repeat Sequences; Testing; Therapeutic; Therapeutic Agents; Therapeutic Intervention; Tumor Suppression; Work; anti-cancer therapeutic; base; carcinogenesis; chemotherapeutic agent; chromatin immunoprecipitation; crosslink; endonuclease; gene replacement; genome-wide; human TOP1 protein; improved; insight; interest; nuclease; oxidative damage; prevent; protein complex; reconstitution; repaired; telomere; tumorigenesis; yeast genetics

DESCRIPTION (provided by applicant): Carcinogenesis involves multiple genetic changes that result from errors in repair of DNA damage. Several highly error prone mechanisms for repair of DNA breaks exist which can serve as the source of mutations and drive formation and/or maintenance of a variety of cancers. It is thus of significant public health interest to define how and when cells rely on error prone mechanisms to repair DNA breaks and assess cellular and pathological consequences of genetic alterations associated with these processes. The goal of this proposal is to elucidate the molecular mechanisms of one of these error prone repair mechanisms of DNA breaks in eukaryotes and the newly identified recombination proteins crucial for such recombination reaction. Recombination between tandem repeat sequences is an evolutionary conserved error prone mechanism that repairs DNA breaks by producing sequence deletions. To define genetic component of this recombination process, we screened genes needed for efficient repair of breaks flanking direct repeats with an approach that combines yeast genetics and microarray technology. This screen uncovered two new recombination genes, SLX4 and SAW1, that function in removal of 3' flaps from recombination intermediates. Removal of a 3' flap also depends on the structure specific endonuclease complex, Rad1/Rad10, and dictates cellular tolerance to cancer chemotherapeutic agents, gene targeting, telomere integrity, repair of oxidative damage and suppression of aging. To decipher biochemical and molecular basis of error prone recombination, we plan to define the biochemical properties of Saw1 in recombination and recombination related biological processes including repair of DNA lesions blocking ongoing replication fork progression. We will reconstitute the 3' flap removal process during recombination using purified recombination proteins and a 3' flap DNA. The information will help devise clinical strategies to reduce or eliminate mutagenic repair germane to carcinogenesis and pave the way for improved cancer therapeutics.

描述（由申请人提供）：癌发生涉及多种遗传变化，这些变化是由于 DNA 损伤修复错误而导致的。存在几种极易出错的 DNA 断裂修复机制，它们可以作为突变的来源并驱动多种癌症的形成和/或维持。因此，确定细胞如何以及何时依赖容易出错的机制来修复 DNA 断裂并评估与这些过程相关的遗传改变的细胞和病理后果具有重要的公共卫生意义。该提案的目的是阐明真核生物中 DNA 断裂的易错修复机制之一的分子机制，以及新发现的对于此类重组反应至关重要的重组蛋白。串联重复序列之间的重组是一种进化保守的易错机制，通过产生序列缺失来修复 DNA 断裂。为了定义这一重组过程的遗传成分，我们采用酵母遗传学和微阵列技术相结合的方法，筛选了有效修复直接重复序列侧翼断裂所需的基因。该筛选发现了两个新的重组基因 SLX4 和 SAW1，它们的功能是从重组中间体中去除 3' 瓣。 3' 瓣的去除还取决于结构特异性核酸内切酶复合物 Rad1/Rad10，并决定细胞对癌症化疗药物、基因靶向、端粒完整性、氧化损伤修复和衰老抑制的耐受性。为了破译易错重组的生化和分子基础，我们计划定义 Saw1 在重组和重组相关生物过程中的生化特性，包括修复阻碍正在进行的复制叉进展的 DNA 损伤。我们将使用纯化的重组蛋白和 3' 瓣 DNA 重建重组过程中的 3' 瓣去除过程。这些信息将有助于制定临床策略，以减少或消除与致癌密切相关的突变修复，并为改进癌症治疗铺平道路。