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Study on Genetic Recombination Systems in Eukaryotes

真核生物基因重组系统的研究

基本信息

批准号：
06101003
负责人：
OGAWA Hideyuki
金额：
$ 170.88万
依托单位：
Iwate College of Nursing (1998)Osaka University (1994-1997)
依托单位国家：
日本
项目类别：
Grant-in-Aid for Specially Promoted Research
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1998
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-06101003/
关键词：
non-homologous end joining nuclease activity of Mre11 protein RecA protein strand-transfer activity of Rad51 Rad52 protein REP protein initiation of meiotic recombination processing from DSB ends MRE11,RAD50&XRS2遺伝子 MRE11,RAD50 & XRS2遺伝子

项目摘要

We set three main subjects as follows. (1) Elucidation of away of recognition in abase sequence between two homologous DNA molecules. (2) Analysis of structures and functions of recombination apparatuses for initiation and formation of recombination intermediates. (3) Analysis of chromosome structures required for recombination process.The following are the prominent results that we obtained for a five-year period of this investigation. (1) Structure of RecA-DNA complexes was analyzed by NMR spectroscopy. Analysis revealed that the DNA structure in the complexes contained novel deoxyribose-base stacking and bases of the single-stranded DNA were spaced out nearly 0.5 run. This novel structure prompted us to propose a new model for a recognition mechanism of homologous base sequence in homologous pairing. (2) We analyzed the function of the Mre 11 protein that played a central role in the initiation of meiotic recombination. The Mre 11 protein was involved in DNA double-strand break (DSB … More ) formation and carried out processing from the DSBs with its nuclease activities. In addition, Mre 11 protein also carried out non-homologous end joining reaction of DSBs and was involved in illegitimate recombination through the reaction. These findings suggest that the Mre 11 protein acts at the junction of homologous recombination pathway and illegitimate recombination pathway and may provide a breakthrough in improving a low frequency of gene targeting in eukaryotic cells. (3) Strand-transfer activity was observed for Rad5l protein at a high level as RecA protein by addition of Rad52 and REP proteins in the reaction mixture. This finding will accelerate the analysis of molecular mechanism of formation of recombination intermediates in eukaryotes.All results obtained contributed directly to the research field with repair of DSBs produced by irradiation of ionizing radiation. Furthermore they proposed new research problems, what a relationship is existed between meiotic recombination and DNA damage check point system, and how the Mre 11 protein is invoked in maintenance of a telomere length or repeated nucleotide sequences. Less

我们设定了三个主要课题如下。(1)两个同源DNA分子之间的DNA序列识别的偏离的解释。(2)重组装置的结构和功能分析，用于启动和形成重组中间体。(3)重组过程所需的染色体结构分析。以下是我们在五年的调查中获得的主要结果。(1)通过NMR光谱分析RecA-DNA复合物的结构。分析表明，复合物中的DNA结构包含新的脱氧核糖碱基堆积和单链DNA的碱基间隔近0.5 nm。这种新的结构促使我们提出了一个新的模式，在同源配对的同源碱基序列的识别机制。(2)我们分析了Mre 11蛋白的功能，它在减数分裂重组的启动中起着核心作用。Mre 11蛋白参与DNA双链断裂（DSB ...更多信息）形成，并利用其核酸酶活性从DSB进行加工。此外，Mre 11蛋白还进行DSB的非同源末端连接反应，并通过该反应参与非法重组。这些发现表明，Mre 11蛋白在同源重组途径和非法重组途径的连接处起作用，并且可能在改善真核细胞中的低频率基因打靶方面提供突破。(3)通过在反应混合物中加入Rad 52和REP蛋白质，观察到Rad 51蛋白质的链转移活性与RecA蛋白质一样高。这一发现将促进对真核生物重组中间体形成的分子机制的分析，为电离辐射损伤后DSB的修复研究提供直接的理论依据。此外，他们还提出了新的研究问题，即减数分裂重组与DNA损伤检查点系统之间存在什么关系，以及Mre 11蛋白如何被调用以维持端粒长度或重复的核苷酸序列。少