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Chromosome partitioning at the initiation of sporulation in Bacillus subtilis

枯草芽孢杆菌孢子形成起始时的染色体分配

基本信息

批准号：
07456048
负责人：
KOBAYASHI Yasuo
金额：
$ 1.22万
依托单位：
Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1995
资助国家：
日本
起止时间：
1995 至 1996
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-07456048/
关键词：
Bacillus subtilis spoOJ operon initiation of sporulation roj SpoOA chromosome partitioning SpoOJA SpoOJB Bacillus subtilis 胞子形成 spoOJ

项目摘要

The mechanism of chromosome partitioning at the initiation of sporulation in Bacillus subtilis is so far not much studied, but it is a very important subject concerning the cellular differentiation and chromosome replication. Sporulation initiation signals are sensed by the phosphorelay system and the sporulation is initiated by the accumulation of the response regulator spoOA-P.Several environ-mental signals, such as nutrient deprivation, DNA replication and partitioning, cell division, and cell density, are input into the phosphorelay system and regulate the concentration of the active SpoOA.The spoOJ operon (spoOJA-spoOJB) is located near the replication origin of the B.subtilis chromosome. It is a homology of the parA-parB operon which plays an important role in the plasmid partitioning. The roj, which encodes a SpoOJB homolog, is located upstream of the spoOJ operon.In the present study we have analyzed the function of these genes. We found that (i) spoOJB is necessary for the chromosome partitioning of the vegetative cells, (ii) SpoOJA protein represses the phosphorelay and the asymmetric septation or chromosome partitioning at the initiation of sporulation (stage I), and (iii) SpoOJB protein represses the function of SpoOJA ; i.e.SpoOJB participates in the chromosome partitioning at the initiation of sporulation through SpoOJA.The fact that the SpoOJA/SpoOJB repress the phosphorelay and chromsome partitioning suggests that SpoOJA/SpoOJB coordinate these mechanisms. We also analyzed the transcriptional regulation of the spoOJ operon and found that Roj protein is a repressor of the spoOJ operon and the expression of the spoOJ operon is repressed by SpoOA at the initiation of sporulation.

迄今为止，对枯草芽孢杆菌产孢起始时染色体分配机制的研究还不多，但它是有关细胞分化和染色体复制的一个重要课题。产孢启动信号由磷接力系统感知，并通过响应调节因子spoa - p的积累启动产孢。一些环境信号，如营养剥夺、DNA复制和分裂、细胞分裂和细胞密度，被输入到磷接力系统并调节活性spoa的浓度。spoj操纵子（spoOJA-spoOJB）位于枯草芽孢杆菌染色体复制起点附近。它是在质粒分配中起重要作用的parA-parB操纵子的同源物。编码一个SpoOJB同源物的roj位于spoOJ操纵子的上游。在本研究中，我们分析了这些基因的功能。研究发现：(1)spojb对营养细胞的染色体分配是必需的，(2)在孢子形成初期（第1阶段），SpoOJA蛋白抑制磷传递和不对称分裂或染色体分配，(3)spoOJB蛋白抑制SpoOJA的功能；即，通过spoojb参与孢子形成起始时的染色体分裂。SpoOJA/SpoOJB抑制磷接力和染色体分裂的事实表明，SpoOJA/SpoOJB协调了这些机制。我们还分析了spoj操纵子的转录调控，发现Roj蛋白是spoj操纵子的抑制因子，并且在孢子形成时，spoOJ操纵子的表达受到spoa的抑制。