Mechanism of the initial steps in transcription-coupled DNA repair (TCR)

转录偶联 DNA 修复 (TCR) 初始步骤的机制

基本信息

批准号：
7966207
负责人：
MIKHAIL KASHLEV
金额：
$ 28.79万
依托单位：
DIVISION OF BASIC SCIENCES - NCI
依托单位国家：
美国
项目类别：
财政年份：
资助国家：
美国
起止时间：
至
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/7966207
关键词：
Active Sites Address Binding Chromatin Cisplatin Cockayne Syndrome Complex DNA DNA Damage DNA Polymerase II DNA Repair DNA Repair Pathway DNA lesion DNA-dependent ATPase Development Enzymes Escherichia coli Eukaryota Event Excision Family Genes Genetic Genetic Transcription Goals Homologous Gene In Vitro Investigation Lead Lesion Location Mammalian Cell Mediating Molecular Nature Nucleosomes Nucleotide Excision Repair Pathway interactions Play Polymerase Positioning Attribute Proteins Protocols documentation Pyrimidine Dimers Recombinant DNA Recruitment Activity Research Resistance Role SAGA Saccharomyces cerevisiae Signal Transduction Site System Thymidine Transcription Elongation Transcription Initiation Transcription-Coupled Repair Type II Cockayne Syndrome UV induced DNA damage Ubiquitination Variant Yeasts adduct analog base chemotherapeutic agent crosslink dimer genetic analysis helicase histone modification human TYRP1 protein insight member mutant novel originality repaired response success transcription factor S-II transcription factor TFIIE transcription factor TFIIH tumor ubiquitin ligase

项目摘要

The mechanism of TCR initiation in S. cerevisiae is distinct from the TCR initiation in mammalian cells. While deletion of the Cockayne Syndrome Group B gene severely inhibits TCR in the mammalian cells, deletion of its yeast homologue Rad26 only slightly impairs the TCR. Genetic analyses strongly suggest two alternative TCR subpathways in yeast. The first, dominant pathway is probably initiated by Pol II interaction with Rad26, and is dependent on a non-essential Pol II subunit Rpb4. The second TCR pathway becomes prominent in the absence of Rpb4, and is dependent on another non-essential Pol II subunit Rpb9. The mechanism of the Rpb9-mediated TCR pathway is not well understood. Its investigation by genetic means has been hampered by the lack of the RPB4/RPB9 double deletion mutant, which is likely to be lethal. Analysis of the Rpb9-dependent pathway in yeast may provide important insights into the Pol II-related events during TCR. The location of the Rpb9 subunit on the perimeter of Pol II suggests its possible function in recruiting NER factors to the damaged site. Rpb9 is involved in multiple-transcription related functions such as transcription initiation (selection of the start site), transcription elongation, and recently in ubiquitination and degradation of rpb1 in response to UV-induced DNA damage. This subunit also interacts with a plethora of factors involved in transcription elongation and histone modification (like TFIIS, TFIIE, and SAGA). Which of these factors act as a Rad26 analogue in the Rpb9-mediated TCR pathway remains to be identified.

酿酒酵母中TCR启动的机制与哺乳动物细胞的TCR启动不同。删除Cockayne综合征B基因的删除严重抑制了哺乳动物细胞中的TCR，但删除其酵母同源物rad26仅略微损害了TCR。遗传分析强烈表明酵母中的两个替代性TCR子路口。第一个主要途径可能是由Pol II与RAD26相互作用引发的，并且取决于非必需的POL II亚基RPB4。在不存在RPB4的情况下，第二个TCR途径变得突出，并且取决于另一个非必需的POL II亚基RPB9。 RPB9介导的TCR途径的机制尚不清楚。由于缺乏RPB4/RPB9双重缺失突变体，其遗传手段的调查受到了阻碍，这可能是致命的。对酵母中RPB9依赖性途径的分析可能会为TCR期间与POL II相关事件提供重要的见解。 RPB9亚基在POL II周围的位置表明其在招募NER因素到受损部位的可能功能。 RPB9参与了多转录相关的功能，例如转录起始（开始位点的选择），转录伸长率，以及最近响应UV诱导的DNA损伤的RPB1的泛素化和降解。该亚基还与涉及转录伸长和组蛋白修饰的因素相互作用（例如TFIIS，TFIIE和SAGA）。这些因素中的哪一个在RPB9介导的TCR途径中充当Rad26类似物尚待识别。