A novel component of the division-site selection system of Bacillus subtilis and a new mode of action for the division inhibitor MinCD
A novel component of the division-site selection system of Bacillus subtilis and a new mode of action for the division inhibitor MinCD
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DOI：
10.1111/j.1365-2958.2008.06501.x
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发表时间：
2008-12-01
影响因子：
3.6
通讯作者：
Errington, Jeff
中科院分区：
文献类型：
--
作者：
Bramkamp, Marc;Emmins, Robyn;Errington, Jeff
细菌中的细胞分裂是由一个复杂的细胞动力学机制控制的，其中关键的参与者是微管蛋白同源物FtsZ。大多数杆状细菌在分离的姐妹染色体之间的中间细胞处精确分裂。选择正确的细胞分裂部位被认为是由两个负调控系统决定的：阻止染色体附近分裂的类核封闭系统和防止细胞两极不适当分裂的Min系统。在枯草芽孢杆菌中，分裂抑制剂MinCD在细胞极点的募集依赖于DivIVA，这些蛋白质被认为足以满足Min的功能。我们现在已经确定了部门的一个新组成部分-地点选择系统Minj，它连接了DivIVA和Mind。Minj突变体在分裂过程中受到损害，因为MinCD的活性不再局限于细胞极点。虽然MinCD被认为特异性地作用于FtsZ组装，但对MinJ和divIVA突变体的分析表明，它们的分裂阻断发生在FtsZ下游。结果支持这样一种模型，即Min系统的主要功能在于每个细胞周期只允许一轮分裂，而MinCD在多个水平上起作用，以防止不适当的分裂。
Cell division in bacteria is governed by a complex cytokinetic machinery in which the key player is a tubulin homologue, FtsZ. Most rod-shaped bacteria divide precisely at mid-cell between segregated sister chromosomes. Selection of the correct site for cell division is thought to be determined by two negative regulatory systems: the nucleoid occlusion system, which prevents division in the vicinity of the chromosomes, and the Min system, which prevents inappropriate division at the cell poles. In Bacillus subtilis recruitment of the division inhibitor MinCD to cell poles depends on DivIVA, and these proteins were thought to be sufficient for Min function. We have now identified a novel component of the division-site selection system, MinJ, which bridges DivIVA and MinD. minJ mutants are impaired in division because MinCD activity is no longer restricted to cell poles. Although MinCD was thought to act specifically on FtsZ assembly, analysis of minJ and divIVA mutants showed that their block in division occurs downstream of FtsZ. The results support a model in which the main function of the Min system lies in allowing only a single round of division per cell cycle, and that MinCD acts at multiple levels to prevent inappropriate division.