The novel sigma factor-like regulator RpoQ controls luminescence, chitinase activity, and motility in Vibrio fischeri.
The novel sigma factor-like regulator RpoQ controls luminescence, chitinase activity, and motility in Vibrio fischeri.
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作者：
Cao X;Studer SV;Wassarman K;Zhang Y;Ruby EG;Miyashiro T
费氏弧菌是夏威夷短尾乌贼Euprymna sputteropes的细菌共生体，它利用群体感应来控制涉及生物发光、宿主定植和其他生物过程的基因。先前的工作已经表明，AinS/R导向的群体感应也调节rpoQ（VF_A1015）的表达，该基因被注释为RpoS样sigma因子。在这项研究中，我们证明了使用遗传学的RpoQ是相关的，但不同的，静止相西格玛因素RpoS。rpoQ的过表达导致几丁质酶活性升高，但运动性和发光性降低，这三种活性与共生有关。与rpoQ过表达相关的细菌发光的减少发生在培养物中和鱿鱼宿主的发光器官内。这种生物发光的抑制是由于luxICDABEG启动子的抑制。我们的研究结果强调RpoQ作为一种新的调控成分，嵌入在群体信号网络，控制几个生物过程中V. fischeri。群体信号是一种广泛存在的现象，在不同的细菌类群中发挥作用。它最常被发现与与动物或植物宿主相互作用的物种有关，无论是作为互惠者还是病原体，并控制对组织定殖至关重要的基因的表达。我们目前的发现rpoQ，它编码一个新的监管组件的群体信号通路的费氏弧菌。RpoQ是固定相sigma因子RpoS家族中的一种新蛋白。与参与弧菌科群体信号通路的许多其他调节蛋白不同，RpoQ的分布似乎仅限于两个密切相关的物种。该调节器的作用是增强一些群体信号输出（几丁质酶活性），同时抑制其他（发光）。我们认为RpoQ可能是费氏弧菌最近进化或获得的成分，为该生物体提供了额外的调节水平，以调节其现有的群体信号传导途径。
Vibrio fischeri, the bacterial symbiont of the Hawaiian bobtail squid, Euprymna scolopes, uses quorum sensing to control genes involved in bioluminescence, host colonization, and other biological processes. Previous work has shown that AinS/R-directed quorum sensing also regulates the expression of rpoQ (VF_A1015), a gene annotated as an RpoS-like sigma factor. In this study, we demonstrate using phylogenetics that RpoQ is related to, but distinct from, the stationary-phase sigma factor RpoS. Overexpression of rpoQ results in elevated chitinase activity but decreased motility and luminescence, three activities associated with symbiosis. The reduction in bacterial luminescence associated with the overexpression of rpoQ occurs both in culture and within the light-emitting organ of the squid host. This suppression of bioluminescence is due to the repression of the luxICDABEG promoter. Our results highlight RpoQ as a novel regulatory component, embedded in the quorum-signaling network that controls several biological processes in V. fischeri. Quorum signaling is a widely occurring phenomenon that functions in diverse bacterial taxa. It is most often found associated with species that interact with animal or plant hosts, either as mutualists or pathogens, and controls the expression of genes critical to tissue colonization. We present the discovery of rpoQ, which encodes a new regulatory component in the quorum-signaling pathway of Vibrio fischeri. RpoQ is a novel protein in the RpoS family of stationary-phase sigma factors. Unlike many other regulatory proteins involved in the quorum-signaling pathways of the Vibrionaceae, the distribution of RpoQ appears to be restricted to only two closely related species. The role of this regulator is to enhance some quorum-signaling outputs (chitinase activity) while suppressing others (luminescence). We propose that RpoQ may be a recently evolved or acquired component in V. fischeri that provides this organism with an additional level of regulation to modulate its existing quorum-signaling pathway.