DNA Replication Fidelity and Cancer

DNA 复制保真度与癌症

• 批准号: 6776235
• 负责人: BRADLEY D PRESTON
• 金额: $ 24.86万
• 依托单位: UNIVERSITY OF WASHINGTON
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-04-06 至 2008-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6776235
• 关键词: DNA damage; DNA directed DNA polymerase; DNA repair; DNA replication; carcinogenesis; cytogenetics; gene mutation; genetic transcription; genetically modified animals; laboratory mouse; lung neoplasms; neoplasm /cancer genetics; nucleic acid denaturation; phenotype; skin neoplasms

DESCRIPTION (provided by applicant): Normal cells replicate their genomes with high fidelity (approximately 10-10 mutations/nt/replication cycle). This is achieved through the combined actions of polymerase base selectivity, exonucleolytic proofreading (exo), mismatch correction and DNA damage repair. We recently created "knock-in" mice with an inactivating point mutation (Pold1D400A) in the 3'-->5' exonucleolytic proofreading domain of DNA polymerase d (Pol d) and showed that homozygous mutants develop a unique spectrum of early-onset epithelial tumors (skin and lung, but not intestine). Here we propose to use these novel Pol delta exo-mice and derivative cell lines to characterize the role of Pol delta proofreading in the maintenance of genetic stability and avoidance of cancer in mammals. The specific aims are: 1. Characterize the mutator phenotype of Pol delta exo-cells and mice. To ascertain the extent and nature of the mutator phenotype conferred by loss of Pol delta proofreading, we will determine rates, frequencies and spectra of spontaneous mutations arising in Poldelta1D400A cells in culture and tissues in vivo. 2. Examine cooperativity of Pol delta proofreading with mismatch repair (MMR). Mice and cells carrying combinations of Pol delta proofreading and MMR alleles will be studied to assess how these error correction systems cooperate in mammals at the phenotypic level (survival, mutator and cancer phenotypes). Together, these studies will significantly contribute to our understanding of mutator phenotypes in cancer and will characterize the contribution of Pol delta proofreading to mutation- and cancer-avoidance in mammals.

描述（由申请人提供）：正常细胞以高保真度复制其基因组（大约 10-10 个突变/nt/复制周期）。这是通过聚合酶碱基选择性、核酸外切校对 (exo)、错配校正和 DNA 损伤修复的综合作用来实现的。我们最近创建了在 DNA 聚合酶 d (Pol d) 的 3'-->5' 核酸外切校对域中具有失活点突变 (Pold1D400A) 的“敲入”小鼠，并表明纯合突变体会形成一系列独特的早发性上皮肿瘤（皮肤和肺，但不是肠道）。在这里，我们建议使用这些新型 Pol delta 外显子小鼠和衍生细胞系来表征 Pol delta 校对在维持哺乳动物遗传稳定性和避免癌症方面的作用。具体目标是： 1. 表征 Pol delta 外切细胞和小鼠的突变表型。为了确定由于 Pol delta 校对缺失而导致的增变表型的程度和性质，我们将确定培养物和体内组织中 Poldelta1D400A 细胞中自发突变的速率、频率和谱。 2. 检查 Pol delta 校对与错配修复 (MMR) 的协同性。将研究携带 Pol delta 校对和 MMR 等位基因组合的小鼠和细胞，以评估这些纠错系统如何在哺乳动物表型水平（生存、突变和癌症表型）上进行合作。 总之，这些研究将极大地促进我们对癌症突变表型的理解，并将描述 Pol delta 校对对哺乳动物突变和癌症避免的贡献。