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.

枯草芽孢杆菌孢子形成起始时的染色体分配机制迄今为止研究较少，但它是细胞分化和染色体复制的一个非常重要的课题。孢子形成起始信号由磷中继系统感应，通过响应调节剂 spoOA-P 的积累启动孢子形成。输入一些环境信号，如营养剥夺、DNA 复制和分配、细胞分裂和细胞密度。进入磷酸中继系统并调节活性 SpoOA 的浓度。 spoOJ 操纵子 (spoOJA-spoOJB) 位于复制起点附近枯草芽孢杆菌染色体。它是 parA-parB 操纵子的同源物，在质粒分配中发挥重要作用。编码 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。我们发现（i）spoOJB对于营养细胞的染色体分配是必需的，（ii）SpoOJA蛋白抑制磷中继和孢子形成起始（第一阶段）时的不对称分隔或染色体分配，以及（iii）SpoOJB蛋白抑制SpoOJA 的功能；即SpoOJB通过SpoOJA参与孢子形成起始时的染色体分配。SpoOJA/SpoOJB抑制磷酸传递和染色体分配的事实表明SpoOJA/SpoOJB协调这些机制。我们还分析了 spoOJ 操纵子的转录调控，发现 Roj 蛋白是 spoOJ 操纵子的阻遏蛋白，并且 spoOJ 操纵子的表达在孢子形成起始时受到 SpoOA 的抑制。