Chromosome Translocation Inflates Bacillus Forespores and Impacts Cellular Morphology
Chromosome Translocation Inflates Bacillus Forespores and Impacts Cellular Morphology
复制标题
DOI：
10.1016/j.cell.2018.01.027
复制
发表时间：
2018-02-08
期刊：
影响因子：
64.5
通讯作者：
Pogliano, Kit
中科院分区：
文献类型：
--
作者：
Lopez-Garrido, Javier;Ojkic, Nikola;Pogliano, Kit
不同细胞组分的物理化学性质共同决定细菌细胞形状的方法仍然知之甚少。在这里，我们调查了程序化的细胞形状变化枯草芽孢杆菌孢子形成过程中，当一个杆状的营养细胞转化为卵形孢子。不对称的细胞分裂产生一个较大的母细胞和一个较小的半球形前孢子。隔膜将前孢子染色体捕获，通过SpoIIIE将其转移到前孢子中。同时，前孢子大小增加，因为它被重塑成一个卵形体。使用遗传学，延时显微镜，冷冻电子断层扫描，和数学建模，我们证明，前孢子生长依赖于膜合成和SpoIIIE介导的染色体易位，但不是肽聚糖或蛋白质合成。我们的数据表明，水合类核膨胀和膨胀的前孢子，取代核糖体的细胞周边，伸展隔膜肽聚糖，重塑前孢子。我们的研究结果说明了核心细胞成分之间简单的生物物理相互作用如何影响细胞形态。
The means by which the physicochemical properties of different cellular components together determine bacterial cell shape remain poorly understood. Here, we investigate a programmed cell-shape change during Bacillus subtilis sporulation, when a rod-shaped vegetative cell is transformed to an ovoid spore. Asymmetric cell division generates a bigger mother cell and a smaller, hemispherical forespore. The septum traps the forespore chromosome, which is translocated to the forespore by SpoIIIE. Simultaneously, forespore size increases as it is reshaped into an ovoid. Using genetics, timelapse microscopy, cryo-electron tomography, and mathematical modeling, we demonstrate that forespore growth relies on membrane synthesis and SpoIIIE-mediated chromosome translocation, but not on peptidoglycan or protein synthesis. Our data suggest that the hydrated nucleoid swells and inflates the forespore, displacing ribosomes to the cell periphery, stretching septal peptidoglycan, and reshaping the forespore. Our results illustrate how simple biophysical interactions between core cellular components contribute to cellular morphology.