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MECHANISMS OF DNA REPAIR IN ACTIVE GENES

活性基因中的 DNA 修复机制

基本信息

批准号：
2183211
负责人：
ISABEL W MELLON
金额：
$ 11.26万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
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

项目摘要

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用于消除 DNA 损伤。我们最近揭示了 DNA 的一个新特征维修;紫外线诱导的嘧啶二聚体被选择性去除来自哺乳动物细胞和大肠杆菌中活性基因的转录 DNA 链。大肠杆菌。现在的工作重点是表征链的机制具体修复。大肠杆菌的研究将成为特色，因为遗传和生化工具的可用性。采取的方法包括：修复乳糖操纵子将在相关突变体中进行研究，以确定链所需的基因可能机制的具体修复和测试模型。转录于将测量操纵子以检验链特异性的假设修复对于紫外线照射后的细胞存活很重要，因为它有助于维持关键转录本的水平。转录的影响修复率操纵子内的修复率，以及将研究化学损伤的消除，以检验以下假设：损伤阻断的RNA聚合酶复合物充当链-的信号具体修复。核糖体和转移RNA基因的修复将是研究以确定链特异性修复是否受到 RNA 转录时的加工或构象。型号将使用纯化的核苷酸在体外测试链特异性修复的效果切除修复蛋白。我们的计划是确定参与者并了解管理规则大肠杆菌中的链特异性修复。在该系统中获得的结果将然后用于指导我们在其他系统中的调查。