Molecular Mechanism of Bacterial Chromosome Partitioning dependent on a Centromere like site migS

依赖于着丝粒样位点 migS 的细菌染色体分配的分子机制

基本信息

批准号：
16370082
负责人：
NIKI Hironori
金额：
$ 9.54万
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 (B)
财政年份：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

项目摘要

We have found a centromere-like element (migS) on the Escherichia coli genome. We searched gene products that genetically interact with migS. Transposon (Tn) insertion mutations of phoU showed a growth defect under migS deletion mutation. It was reported that PhoU functions in phosphate uptake and intercellular phosphate metabolism, although several group claimed those were not its primary functions. The phoU Tn insertion mutant (phoU : : Tn) lacked a few amino acid residues from the carboxyl terminal of phoU gene, and the null mutant did not show the synthetic lethal phenotype with migS mutant. phoU::Tn cells showed mislocated nucleoid from centre of the cells, while in wild type cells have the nucleoid at central region of the cell. Daughter nucleoids were not clearly separated at cell division in the mutant. In fact, frequency of DNA-less cells increased in the phoU mutant. This phenotype was exaggerated in slmA deficient cells where septum inhibition mechanism over unseparated nucl … More eoids was absent. In ΔslmA, phoU : : Tn double mutant cells, frequency of anucleate cells were increased compared to the wild type cells and guillotine typed cells were appeared. We concluded that the truncated PhoU protein perturbed correct positioning of daughter nucleoids and this could lead mitotic catastroph. Furthermore, we would like to focus on study of the molecular mechanism for bipolar migration of DNA in a bacterial cell. Although actin-like proteins have been found in prokaryotes, a motor function to partition chromosomes into daughter cells has not yet been identified on bipolar migration of the chromsome. Presumably, a motor protein works on the process to generate a driving force. Investigation of the molecular mechanism of migS dependent migration is providing vital new clues as how the putative motor protein contributes to chromosome partitioning. Proteomics approaches have already been identified two proteins as migS binding proteins. Further investigation of the genes that encode the migS binding proteins have already been carried out, and the results indicates the genes would be involved in bipolar migration of migS Less

我们在大肠杆菌基因组上发现了一个类似着丝粒的元件（migS），我们搜索了与 phoU 的转座子（Tn）插入突变相关的基因产物，据报道，PhoU 具有生长缺陷。 phoU Tn 插入突变体 (phoU : : Tn) 缺乏一些氨基酸。 phoU 基因羧基末端的残基，并且无效突变体没有显示出与 migS 突变体相同的合成致死表型 phoU::Tn 细胞显示出细胞中心的类核错位，而在野生型细胞中，类核位于 phoU 基因的中心区域。在突变体中，子核在细胞分裂时没有明显分离。事实上，在 phoU 突变体中，这种表型被夸大了。 slmA 缺陷细胞，其中未分离核的隔膜抑制机制不存在。在 ΔslmA，phoU :: Tn 双突变细胞中，与野生型细胞相比，无核细胞的频率增加，并且出现了断头台型细胞。截短的 PhoU 蛋白扰乱了子核的正确定位，这可能导致有丝分裂灾难。研究细菌细胞中 DNA 双极迁移的分子机制，尽管在原核生物中发现了肌动蛋白样蛋白，但尚未确定染色体双极迁移的运动功能。运动蛋白在产生驱动力的过程中发挥作用，对 migS 依赖性迁移的分子机制的研究提供了重要的新线索，因为蛋白质组学方法已经确定了两种蛋白质： migS 结合蛋白的进一步研究已经进行，结果表明这些基因可能参与 migS Less 的双极迁移。