Characterization of CrgA, a New Partner of the Mycobacterium tuberculosis Peptidoglycan Polymerization Complexes
Characterization of CrgA, a New Partner of the Mycobacterium tuberculosis Peptidoglycan Polymerization Complexes
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DOI：
10.1128/jb.00188-11
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发表时间：
2011-07-01
影响因子：
3.2
通讯作者：
Rajagopalan, M.
中科院分区：
文献类型：
--
作者：
Plocinski, P.;Ziolkiewicz, M.;Rajagopalan, M.
结核分枝杆菌Rv 0011 c基因产物在细胞分裂中的作用在很大程度上是未知的，Rv 0011 c基因产物是链霉菌CrgA蛋白的同源物，其负责协调生孢子气生菌丝中的生长和胞质分裂。我们发现，增强的青色荧光蛋白-M。结核病CrgA（ECFP-CrgA（MT））融合蛋白定位于耻垢分枝杆菌的细胞膜、中间细胞和细胞极区。此外，ECFP-CrgAMT融合蛋白与FtsZ增强的黄色荧光蛋白（EYFP）在M.恶臭细菌双杂交试验表明，M.结核病CrgA与FtsZ、FtsQ以及B类青霉素结合蛋白FtsI（PBPB）和PBPA的结合。在FtsZ耗尽的条件下，CrgA（MT）的中细胞定位严重受损，这表明CrgA在FtsZ环组装后定位于中细胞区域。M.具有降低的CrgA水平的结核病细胞比野生型细胞更长且生长更慢，这表明细胞分裂缺陷，而CrgA过量产生没有显示生长缺陷。分枝耻垢病Delta crgA菌株表现出隆起的细胞形态、具有链状表型的细长细胞、具有极性球状结构的细胞和适度的生长缺陷。FtsZ和FtsI水平在产生改变的CrgA水平的细胞中不受影响。GFP-FtsI的隔膜和膜定位通过CrgA过量产生而增强，并且在Delta crgA菌株中减弱，这表明CrgA的一个作用是促进和/或稳定FtsI定位。总的来说，这些数据表明，CrgA是分枝杆菌细胞分裂复合体的一个新成员，并可能促进隔膜形成。
The role(s) in cell division of the Mycobacterium tuberculosis Rv0011c gene product, a homolog of the Streptomyces CrgA protein that is responsible for coordinating growth and cytokinesis in sporogenic aerial hyphae, is largely unknown. We show that an enhanced cyan fluorescent protein-M. tuberculosis CrgA (ECFP-CrgA(MT)) fusion protein is localized to the cell membrane, midcell, and cell pole regions in Mycobacterium smegmatis. Furthermore, the ECFP-CrgAMT fusion protein colocalized with FtsZ-enhanced yellow fluorescent protein (EYFP) in M. smegmatis. Bacterial two-hybrid assays indicated strong interactions of M. tuberculosis CrgA with FtsZ, FtsQ, and the class B penicillin-binding proteins, FtsI (PBPB) and PBPA. The midcell localization of CrgA(MT) was severely compromised under conditions of FtsZ depletion, which indicated that CrgA localizes to the midcell region after assembly of the FtsZ ring. M. tuberculosis cells with reduced CrgA levels were elongated and grew more slowly than wild-type cells, which indicated defects in cell division, whereas CrgA overproduction did not show growth defects. A M. smegmatis Delta crgA strain exhibited a bulged cell morphology, elongated cells with a chain-like phenotype, cells with polar bulbous structures, and a modest growth defect. FtsZ and FtsI levels were not affected in cells producing altered levels of CrgA. Septal and membrane localization of GFP-FtsI was enhanced by CrgA overproduction and was diminished in a Delta crgA strain, which indicates that one role of CrgA is to promote and/or stabilize FtsI localization. Overall, these data indicate that CrgA is a novel member of the cell division complex in mycobacteria and possibly facilitates septum formation.