RNase E maintenance of proper FtsZ/FtsA ratio required for nonfilamentous growth of Escherichia coli cells but not for colony-forming ability
RNase E maintenance of proper FtsZ/FtsA ratio required for nonfilamentous growth of Escherichia coli cells but not for colony-forming ability
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DOI：
10.1128/jb.00367-06
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发表时间：
2006-07-01
影响因子：
3.2
通讯作者：
Cohen, Stanley N.
中科院分区：
文献类型：
--
作者：
Tamura, Masaru;Lee, Kangseok;Cohen, Stanley N.
大肠杆菌的RNase E编码基因的失活或缺失导致细菌细胞在液体培养物中生长为丝状链（K. Goldblum和D. Apirion，J. Bacteriol. 146：128-132，1981）和在固体培养基上丧失集落形成能力（CFA）。RNase E功能障碍也与ftsQAZ转录物的异常加工有关（K. Cam，G.罗马，H. M. Krisch和J. - P. Bouche，Nucleic Acids Res.24：3065-3070，1996），其编码在细胞分裂期间隔膜形成中具有中心作用的蛋白质。我们在这里表明，RNase E调节FtsZ和FtsA蛋白的相对丰度，RNase E耗竭导致FtsZ减少，FtsA增加，从而改变FtsZ/FtsA比率。然而，虽然在一个无效突变细菌中FtsZ水平恢复到正常逆转了表达表型，但它不能恢复CFA。相反，在rne缺失的细菌中过表达相关的RNA酶，RNA酶G，恢复CFA，如先前报道的，而不影响FtsZ丰度。我们的研究结果表明，RNase E活性是维持大肠杆菌中FtsZ和FtsA蛋白的适当细胞比例所必需的。但FtsZ缺陷并不能解释缺乏RNase E的细胞不能存活。
Inactivation or deletion of the RNase E-encoding rne gene of Escherichia coli results in the growth of bacterial cells as filamentous chains in liquid culture (K. Goldblum and D. Apirion, J. Bacteriol. 146:128-132, 1981) and the loss of colony-forming ability (CFA) on solid media. RNase E dysfunction is also associated with abnormal processing of ftsQAZ transcripts (K. Cam, G. Rome, H. M. Krisch, and J.-P. Bouche, Nucleic Acids Res. 24:3065-3070, 1996), which encode proteins having a central role in septum formation during cell division. We show here that RNase E regulates the relative abundances of FtsZ and FtsA proteins and that RNase E depletion results in decreased FtsZ, increased FtsA, and consequently an altered FtsZ/FtsA ratio. However, while restoration of the level of FtsZ to normal in rne null mutant bacteria reverses the filamentation phenotype, it does not restore CFA. Conversely, overexpression of a related RNase, RNase G, in rne-deleted bacteria restores CFA, as previously reported, without affecting FtsZ abundance. Our results demonstrate that RNase E activity is required to maintain a proper cellular ratio of the FtsZ and FtsA proteins in E. coli but that FtsZ deficiency does not account for the nonviability of cells lacking RNase E.