The Vibrio cholerae FlgM homologue is an anti-σ28 factor that is secreted through the sheathed polar flagellum
The Vibrio cholerae FlgM homologue is an anti-σ28 factor that is secreted through the sheathed polar flagellum
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DOI：
10.1128/jb.186.14.4613-4619.2004
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发表时间：
2004-07-01
影响因子：
3.2
通讯作者：
Klose, KE
中科院分区：
文献类型：
--
作者：
Correa, NE;Barker, JR;Klose, KE
霍乱弧菌有一个单一的极鞘鞭毛，推动这种细菌的细胞。鞭毛合成、运动性和趋化性都与这种人类病原体的毒力有关。霍乱弧菌表达鞭毛基因的层次组成的西格玛（54）和西格玛（28）依赖性转录。在其他细菌中，sigma（28）转录活性由反sigma（28）因子FlgM控制。我们证明了霍乱弧菌FlgM同源物（i）与σ（28）物理相互作用，（ii）对一些霍乱弧菌σ（28）依赖性鞭毛启动子具有抑制作用，以及（iii）通过极性鞘鞭毛分泌，与抗σ（28）活性一致。有趣的是，FlgM对所有σ（28）依赖性启动子不具有一致的抑制作用，如通过测量缺乏FlgM（Δ flgAl）或不能分泌（Δ flF）的细胞中的σ（28）依赖性转录所确定的。对DeltafliF菌株的进一步分析显示，这种鞭毛组装阻断导致III类（FlrC-和sigma（54）-依赖性）和IV类（sigma（28）-依赖性）鞭毛转录的减少，但不导致II类（FIrA-和sigma（54）-依赖性）鞭毛转录的减少。霍乱弧菌flgM和fliA（编码sigma（28））突变体在其定殖幼小鼠肠的能力（毒力的量度）方面仅受到适度影响。我们的研究结果表明，霍乱弧菌FlgM的功能作为一个抗σ（28）因子，鞘鞭毛是非结构蛋白的分泌能力。
Vibrio cholerae has a single polar sheathed flagellum that propels the cells of this bacterium. Flagellar synthesis, motility, and chemotaxis have all been linked to virulence in this human pathogen. V. cholerae expresses flagellar genes in a hierarchy consisting of sigma(54)- and sigma(28)-dependent transcription. In other bacteria, sigma(28) transcriptional activity is controlled by an anti-sigma(28) factor, FlgM. We demonstrate that the V. cholerae FlgM homologue (i) physically interacts with sigma(28), (ii) has a repressive effect on some V. cholerae sigma(28)-dependent flagellar promoters, and (iii) is secreted through the polar sheathed flagellum, consistent with anti-sigma(28) activity. Interestingly, FlgM does not have a uniform repressive effect on all sigma(28)-dependent promoters, as determined by measurement of sigma(28)-dependent transcription in cells either lacking FlgM (DeltaflgAl) or incapable of secretion (DeltafliF). Further analysis of a DeltafliF strain revealed that this flagellar assembly block causes a decrease in class III (FlrC- and sigma(54)-dependent) and class IV (sigma(28)-dependent), but not class II (FIrA- and sigma(54)-dependent), flagellar transcription. V. cholerae flgM and fliA (encodes sigma(28)) mutants were only modestly affected in their ability to colonize the infant mouse intestine, a measure of virulence. Our results demonstrate that V. cholerae FlgM functions as an anti-sigma(28) factor and that the sheathed flagellum is competent for secretion of nonstructural proteins.