MECHANISMS OF DNA REPAIR IN ACTIVE GENES

活性基因中的 DNA 修复机制

• 批准号: 3468346
• 负责人: ISABEL W MELLON
• 金额: $ 9.96万
• 依托单位: UNIVERSITY OF KENTUCKY
• 依托单位国家: 美国
• 财政年份: 1991
• 资助国家: 美国
• 起止时间: 1991-01-01 至 1995-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/3468346
• 关键词: DNA directed RNA polymerase; DNA repair; Escherichia coli; RNA biosynthesis; acetylaminofluorene; cell growth regulation; conformation; genetic models; genetic transcription; ionizing radiation; lac operon; lactose; mutant; nucleic acid sequence; operon; protein purification; psoralens; pyrimidine dimers; radiation genetics; radiation sensitivity; ribosomal RNA; tissue /cell culture; transfer RNA; ultraviolet radiation

Our long-term objective is to understand the molecular mechanisms cells use for removing DNA damage. We have recently revealed a novel feature of DNA repair; ultraviolet light-induced pyrimidine dimers are selectively removed from the transcribed DNA strands of active gene in mammalian cells and E. coli. Efforts will now focus on characterizing the mechanism of strand- specific repair. Studies in E. coli will be featured because of the availability of genetic and biochemical tools. Approaches to be taken include the following: Repair of the lactose operon will be studied in relevant mutants to identify genes required for strand- specific repair and test models of possible mechanisms. Transcription in the operon will be measured to test the hypothesis that strand-specific repair is important for cell survival after UV-irradiation because it helps maintain levels of critical transcripts. The influence of transcription rates on repair rates the location of repair within the operon, and the removal of chemical damage will be studied to test the hypothesis that lesion-blocked RNA polymerase complex serves as a signal for strand- specific repair. Repair of ribosomal and transfer RNA genes will be studied to determine if strand-specific repair is influenced by the processing or conformation of the RNA as it is being transcribed. Models of strand-specific repair will be tested in vitro using purified nucleotide excision repair proteins. Our plan is to identify the participants and learn the rules that govern strand-specific repair in E. coli. Results obtained in this system will then be used to direct our investigation in other systems.

我们的长期目标是了解细胞使用的分子机制 去除DNA损伤 我们最近发现了DNA的一个新特征 修复;紫外光诱导的嘧啶二聚体被选择性地去除 从哺乳动物细胞中活性基因转录的DNA链和E. 杆菌 现在的工作将集中在表征链的机制- 具体修复。 在E.大肠杆菌将是特色，因为 遗传和生物化学工具的可用性。 可采取的方法包括：乳糖操纵子的修复 将在相关突变体中进行研究，以确定链- 可能机制的特定修复和测试模型。 转录 将测量操纵子以检验链特异性 修复对于紫外线照射后的细胞存活很重要，因为它有助于 保持关键成绩单的水平。 转录的影响 修复率是修复在操纵子中的位置， 将研究化学损伤的去除，以检验以下假设： 损伤阻断的RNA聚合酶复合物作为链- 具体修复。 核糖体和转运RNA基因的修复将是 研究以确定链特异性修复是否受到 RNA在转录时的加工或构象。 模型 将使用纯化的核苷酸在体外测试链特异性修复 切除修复蛋白。 我们的计划是确定参与者并学习管理规则 E.杆菌 在该系统中获得的结果将 然后用来指导我们在其他星系的调查