Department of Microbial and Molecular Systems, KU Leuven, Leuven, Belgium.
Department of Biology, KU Leuven, Leuven, Belgium.
Cell Mol Life Sci. 2023 Nov 16;80(12):360. doi: 10.1007/s00018-023-05002-4.
Mechanisms underlying deviant cell size fluctuations among clonal bacterial siblings are generally considered to be cryptic and stochastic in nature. However, by scrutinizing heat-stressed populations of the model bacterium Escherichia coli, we uncovered the existence of a deterministic asymmetry in cell division that is caused by the presence of intracellular protein aggregates (PAs). While these structures typically locate at the cell pole and segregate asymmetrically among daughter cells, we now show that the presence of a polar PA consistently causes a more distal off-center positioning of the FtsZ division septum. The resulting increased length of PA-inheriting siblings persists over multiple generations and could be observed in both E. coli and Bacillus subtilis populations. Closer investigation suggests that a PA can physically perturb the nucleoid structure, which subsequently leads to asymmetric septation.
在克隆细菌兄弟姐妹中，偏离正常细胞大小波动的机制通常被认为是隐匿和随机的。然而，通过仔细研究模式细菌大肠杆菌的受热胁迫群体，我们发现了细胞分裂中存在一种确定性的不对称性，这种不对称性是由细胞内蛋白质聚集体（PA）的存在引起的。虽然这些结构通常位于细胞极区，并在子细胞中不均匀地分离，但我们现在表明，一个极性 PA 的存在会导致 FtsZ 分裂隔膜更远离中心的偏心定位。由此产生的具有 PA 的继承兄弟姐妹的长度增加会持续多代，并且可以在大肠杆菌和枯草芽孢杆菌群体中观察到。进一步的研究表明，PA 可以物理干扰核区结构，随后导致不对称的分隔。
