Noc Corrals Migration of FtsZ Protofilaments during Cytokinesis in Bacillus subtilis.
Noc Corrals Migration of FtsZ Protofilaments during Cytokinesis in Bacillus subtilis.
复制标题
NOC滤波在枯草芽孢杆菌中细胞因子期间FTSZ原丝的迁移。
DOI：
10.1128/mbio.02964-20
复制
发表时间：
2021-02-02
期刊：
影响因子：
6.4
通讯作者：
Jacobson SC
中科院分区：
文献类型：
--
作者：
Yu Y;Zhou J;Gueiros-Filho FJ;Kearns DB;Jacobson SC
在细菌中，FtsZ(Z环)的浓缩结构在中细胞处招募细胞分裂机制，而Z环的形成在染色体上被一种鲜为人知的现象--类核阻塞--所阻止。据报道，在枯草杆菌中，类核闭塞至少部分是由DNA-膜桥蛋白Noc介导的。通过二次分裂而分裂的细菌在细胞的几何中点形成FtsZ环，这些环位于大量复制的类核之间。在枯草芽孢杆菌中，DNA和膜结合的Noc蛋白被认为通过阻止FtsZ环在染色体上形成而参与类核闭塞。为了探索Noc的作用，我们使用时间推移荧光显微镜来监测FtsZ和生长在微流体通道中的细胞的类核。我们的数据表明，Noc不阻止染色体上从头FtsZ环的形成，也不控制细胞分裂位点的选择。相反，Noc将FtsZ聚集在细胞运动环上，并减少原丝在染色体上向未来细胞分裂部位的迁移。此外，我们还证明了FtsZ原丝的移动是由于ZapA结合的局部减少，并且在Noc突变体中观察到的扩散的FtsZ环可以被ZapA的过表达所抑制。因此，Noc在胞质分裂过程中从空间上阻止FtsZ从Z环迁移，并将FtsZ保留在分裂后的极点，以供Min系统完全分解。
In bacteria, a condensed structure of FtsZ (Z-ring) recruits cell division machinery at the midcell, and Z-ring formation is discouraged over the chromosome by a poorly understood phenomenon called nucleoid occlusion. In B. subtilis, nucleoid occlusion has been reported to be mediated, at least in part, by the DNA-membrane bridging protein, Noc. Bacteria that divide by binary fission form FtsZ rings at the geometric midpoint of the cell between the bulk of the replicated nucleoids. In Bacillus subtilis, the DNA- and membrane-binding Noc protein is thought to participate in nucleoid occlusion by preventing FtsZ rings from forming over the chromosome. To explore the role of Noc, we used time-lapse fluorescence microscopy to monitor FtsZ and the nucleoid of cells growing in microfluidic channels. Our data show that Noc does not prevent de novo FtsZ ring formation over the chromosome nor does Noc control cell division site selection. Instead, Noc corrals FtsZ at the cytokinetic ring and reduces migration of protofilaments over the chromosome to the future site of cell division. Moreover, we show that FtsZ protofilaments travel due to a local reduction in ZapA association, and the diffuse FtsZ rings observed in the Noc mutant can be suppressed by ZapA overexpression. Thus, Noc sterically hinders FtsZ migration away from the Z-ring during cytokinesis and retains FtsZ at the postdivisional polar site for full disassembly by the Min system.