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Cross-talk between DNA repaif and recombination : two kinds of mechanisms that are mediated by DNA end-joining

DNA修复和重组之间的串扰：由DNA末端连接介导的两种机制

基本信息

批准号：
10480189
负责人：
IKEDA Hideo
金额：
$ 7.3万
依托单位：
The Kitasato Institute (1999-2001)The University of Tokyo (1998)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2001
项目状态：
已结题

项目摘要

We analysed mechanisms of illegitimate recombination and its relationship with mechanisms of DNA repair, using newly developed assay systems for illegitimate recombination in Escherichia coli, budding yeast, fission yeast and mouse. Based on the analyses of E.coil DNA gyrase mutants that confer a hyper-recombination phenotype, we showed that several α-helix structures of DNA gyrase plays an important role in illegitimate recombination. It is also shown that E.coil DNA binding protein HU has an activity that suppress DNA gyrasemediated illegitimate recombination, thus playing a role in regulation of the recombination. We have also found that DnaB helicase, exonuclease VIII (RecE), RecT, and DNA ligase are involved in DNA damage-induced illegitimate recombmation in E. coli. Furthermore, many DNA repair enzymes UvrA, UvrB, MutM, Tag, AIkA, ExoI, H-NS, and StpA play important roles for suppression of DNA damage-induced illegitimate recombination. In Saccharomyces cerevisiae, it was found that a DNA topoisomemse II inhibitor induces illegitimate recombination, suggesting that DNA topoisomemse II promotes DNA double-strand bieak and then illegitimate recombination throgh DNA end-joining. It is, on the other hand, shown that Sgsl protein suppresses spontaneous illegitimate recombination. Human BLM and WRN proteins also suppressed illegitimate recombination in budding yeast. In addition, we showed that budding yeast Sccl and fission yeast Dhpl proteins are involved in DNA repair and chromosome segregation and that budding yeast Whip and fission yeast Mogi and Hskl kinase interact with Sgs 1 and Sec 1, respectively. Based on these results, we proposed several models for illegitimate recombination in E.coil and yeast.

我们分析了非法重组的机制及其与DNA修复机制的关系，使用新开发的检测系统在大肠杆菌，芽殖酵母，裂殖酵母和小鼠的非法重组。通过对大肠杆菌DNA旋转酶突变体的分析，发现DNA旋转酶的几种α-螺旋结构在异常重组中起重要作用。大肠杆菌DNA结合蛋白HU具有抑制DNA回旋酶介导的非正常重组的活性，从而在重组的调控中发挥作用。我们还发现DnaB解旋酶、外切核酸酶VIII（RecE）、RecT和DNA连接酶参与了DNA损伤诱导的E.杆菌此外，许多DNA修复酶UvrA、UvrB、MutM、Tag、AIkA、ExoI、H-NS和StpA在抑制DNA损伤诱导的非法重组中起重要作用。在酿酒酵母中，发现DNA拓扑异构酶II抑制剂诱导不正常重组，这表明DNA拓扑异构酶II促进DNA双链断裂，然后通过DNA末端连接进行不正常重组。另一方面，表明Sgsl蛋白抑制自发的非法重组。人BLM和WRN蛋白也抑制芽殖酵母中的非法重组。此外，我们发现，芽殖酵母Sccl和裂殖酵母Dhpl蛋白参与DNA修复和染色体分离，芽殖酵母Whip和裂殖酵母Mogi和Hskl激酶分别与Sgs 1和Sec 1相互作用。基于这些结果，我们提出了几种大肠杆菌和酵母中非法重组的模型。