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Molecular mechanism of microbial DNA partitioning : structure and function

微生物 DNA 分配的分子机制：结构和功能

基本信息

批准号：
17080009
负责人：
NIKI Hironori
金额：
$ 64.32万
依托单位：
National Institute of Genetics
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research on Priority Areas
财政年份：
2005
资助国家：
日本
起止时间：
2005 至 2009
项目状态：
已结题

项目摘要

Plasmids in bacterial cells have the centromere-based segregation system to ensure their faithful transmission to daughter cells, and is being studied as a model system for chromosome partitioning mechanism. We studied the general mechanism underlie these plasmid partitioning machineries, and found that SopA and ParA proteins do not directly pull of push plasmid DNA, but rather guide the plasmids to the right direction by making the gradient of protein concentrations. Notably, the gradient of SopA or ParA proteins were formed from the polymerizing center within the cell (SopA forms a filament within the cell, and ParA locates on the nuclear). We have been investigating transmission mechanism of bacterial chromosome as well. As the chromosome transmission guidance protein, we identified novel factor MigP and a component of the complex I of electron transport chain NuoG. both are membrane associating proteins and we expect DNA transmission mechanism could associates membrane localization.DNA checkpoint mechanism in eukaryotic cells stops the cell cycle progression when the cell suffers from DNA damage. We identified the mechanism also affects DNA repairactivities themselves besides its regulate cell cycle progression. We further studied the checkpoint mechanism in dimorphic yeast system. There we found that Chk1 could induce hyphaformation in response to DNA damage, and thus we defined it as the novel cell cycle regulatory function of DNA checkpoint.

细菌细胞中的质粒具有基于着丝粒的分离系统，以确保其忠实地传递给子细胞，并且正在作为染色体分配机制的模型系统进行研究。我们研究了这些质粒分配机制的一般机制，发现SopA和ParA蛋白并不直接拉动质粒DNA，而是通过形成蛋白质浓度梯度来引导质粒向正确的方向移动。值得注意的是，SopA 或 ParA 蛋白的梯度是由细胞内的聚合中心形成的（SopA 在细胞内形成细丝，而 ParA 位于细胞核上）。我们也一直在研究细菌染色体的传递机制。作为染色体传输引导蛋白，我们鉴定了新因子 MigP 和电子传递链 NuoG 复合物 I 的一个组成部分。两者都是膜相关蛋白，我们预计DNA传递机制可能与膜定位相关。当细胞遭受DNA损伤时，真核细胞中的DNA检查点机制会阻止细胞周期的进展。我们发现，除了调节细胞周期进程外，该机制还影响 DNA 修复活性本身。我们进一步研究了二态性酵母系统中的检查点机制。我们发现Chk1可以响应DNA损伤而诱导丝状形成，因此我们将其定义为DNA检查点的新型细胞周期调节功能。