Absence of the Polar Organizing Protein PopZ Results in Reduced and Asymmetric Cell Division in Agrobacterium tumefaciens
Absence of the Polar Organizing Protein PopZ Results in Reduced and Asymmetric Cell Division in Agrobacterium tumefaciens
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DOI：
10.1128/jb.00101-17
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发表时间：
2017-09-01
影响因子：
3.2
通讯作者：
Brown, Pamela J. B.
中科院分区：
文献类型：
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作者：
Howell, Matthew;Aliashkevich, Alena;Brown, Pamela J. B.
根癌农杆菌是一种杆状细菌，在细胞伸长过程中通过极性插入新的肽聚糖而生长。随着细胞周期的进展，在中细胞插入新的肽聚糖以使细胞分裂之前，极处的肽聚糖合成停止。助理新月柄杆菌极性细胞器发育蛋白PopZ的根癌农杆菌同源物已被鉴定为生长极标记物和候选极性生长促进因子。在此，我们描述了PopZ在A.根瘤菌与以前的观察结果一致，我们观察到PopZ特异性定位于野生型细胞的生长极。尽管引人注目的本地化模式的PopZ，我们发现的蛋白质的情况下，不损害极性伸长或引起的肽聚糖组成的重大变化。相反，我们观察到一个非典型的细胞长度分布，包括微细胞，细长细胞，细胞与异位极。大多数微细胞缺乏DNA，表明染色体分离缺陷。此外，典型的细胞分裂蛋白FtsZ和FtsA是错位的，导致细胞收缩的不对称位点。总之，这些数据表明PopZ在染色体分离和细胞分裂的调节中起重要作用。根癌农杆菌是一种细菌性植物病原体，也是一种天然的基因工程菌。然而，很少有人知道的空间和时间的调节细胞壁的生物合成，导致在这种细菌的极性生长。了解A.根癌农杆菌的生长可以允许开发创新以预防疾病或在生物技术应用期间促进生长。最后，由于许多密切相关的植物和动物病原体表现出极性生长，在A.根癌农杆菌可以广泛地应用于设计抗微生物策略。
Agrobacterium tumefaciens is a rod-shaped bacterium that grows by polar insertion of new peptidoglycan during cell elongation. As the cell cycle progresses, peptidoglycan synthesis at the pole ceases prior to insertion of new peptidoglycan at midcell to enable cell division. The A. tumefaciens homolog of the Caulobacter crescentus polar organelle development protein PopZ has been identified as a growth pole marker and a candidate polar growth-promoting factor. Here, we characterize the function of PopZ in cell growth and division of A. tumefaciens. Consistent with previous observations, we observe that PopZ localizes specifically to the growth pole in wild-type cells. Despite the striking localization pattern of PopZ, we find the absence of the protein does not impair polar elongation or cause major changes in the peptidoglycan composition. Instead, we observe an atypical cell length distribution, including minicells, elongated cells, and cells with ectopic poles. Most minicells lack DNA, suggesting a defect in chromosome segregation. Furthermore, the canonical cell division proteins FtsZ and FtsA are misplaced, leading to asymmetric sites of cell constriction. Together, these data suggest that PopZ plays an important role in the regulation of chromosome segregation and cell division.IMPORTANCE A. tumefaciens is a bacterial plant pathogen and a natural genetic engineer. However, very little is known about the spatial and temporal regulation of cell wall biogenesis that leads to polar growth in this bacterium. Understanding the molecular basis of A. tumefaciens growth may allow for the development of innovations to prevent disease or to promote growth during biotechnology applications. Finally, since many closely related plant and animal pathogens exhibit polar growth, discoveries in A. tumefaciens may be broadly applicable for devising antimicrobial strategies.