Early targeting of Min proteins to the cell poles in germinated spores of Bacillus subtilis:: evidence for division apparatus-independent recruitment of Min proteins to the division site
Early targeting of Min proteins to the cell poles in germinated spores of Bacillus subtilis:: evidence for division apparatus-independent recruitment of Min proteins to the division site
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DOI：
10.1046/j.1365-2958.2003.03253.x
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发表时间：
2003-01-01
影响因子：
3.6
通讯作者：
Lewis, PJ
中科院分区：
文献类型：
--
作者：
Harry, EJ;Lewis, PJ
细菌细胞分裂的最早期事件是微管蛋白样蛋白FtsZ在细胞中部组装形成环。在杆状细菌中，Min系统通过抑制FtsZ环的形成在细胞的极区特异性地在分裂位点的放置中起重要作用。Min系统包括MinD和MinC，它们形成抑制剂复合物，并且在枯草芽孢杆菌中包括DivIVA，其确保仅在极性区域中抑制分裂。这三种蛋白质都定位于细胞中部的分裂位点和细胞两极。它们在分裂位点的募集依赖于“早期”和“晚期”分裂蛋白的定位。我们检查了在B萌发和生长后的第一次和第二次细胞分裂期间DivIVA相对于FtsZ的时间和空间定位。枯草芽孢我们发现，虽然FtsZ环组装在中间细胞约一半的细胞周期，DivIVA组装在这个网站上细胞分裂前立即和持续存在的Z环收缩和完成分裂。我们还表明，DivIVA和MinD定位到细胞两极孢子萌发后立即，以及之前的Z环在中间细胞的形式。此外，这些蛋白质被发现存在于成熟的休眠孢子中。这些结果表明，目标的Min蛋白分裂网站并不直接依赖于组装的分裂装置，如前所述，和潜在的极性分裂网站被阻止在细胞周期的最早可能的阶段在萌发的孢子作为一种机制，以确保相等大小的子细胞产生后，细胞分裂。
The earliest event in bacterial cell division is the assembly of a tubulin-like protein, FtsZ, at mid-cell to form a ring. In rod-shaped bacteria, the Min system plays an important role in division site placement by inhibiting FtsZ ring formation specifically at the polar regions of the cell. The Min system comprises MinD and MinC, which form an inhibitor complex and, in Bacillus subtilis, DivIVA, which ensures that division is inhibited only in the polar regions. All three proteins localize to the division site at mid-cell and to cell poles. Their recruitment to the division site is dependent on localization of both 'early' and 'late' division proteins. We have examined the temporal and spatial localization of DivIVA relative to that of FtsZ during the first and second cell division after germination and outgrowth of B. subtilis spores. We show that, although the FtsZ ring assembles at mid-cell about halfway through the cell cycle, DivIVA assembles at this site immediately before cell division and persists there during Z-ring constriction and completion of division. We also show that both DivIVA and MinD localize to the cell poles immediately upon spore germination, well before a Z ring forms at mid-cell. Furthermore, these proteins were found to be present in mature, dormant spores. These results suggest that targeting of Min proteins to division sites does not depend directly on the assembly of the division apparatus, as suggested previously, and that potential polar division sites are blocked at the earliest possible stage in the cell cycle in germinated spores as a mechanism to ensure that equal-sized daughter cells are produced upon cell division.