A distinctive dual-channel quorum-sensing system operates in Vibrio anguillarum
A distinctive dual-channel quorum-sensing system operates in Vibrio anguillarum
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DOI：
10.1111/j.1365-2958.2004.04083.x
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发表时间：
2004-06-01
影响因子：
3.6
通讯作者：
Milton, DL
中科院分区：
文献类型：
--
作者：
Croxatto, A;Pride, J;Milton, DL
许多细菌细胞通过一种称为群体感应的过程，利用可扩散的信号分子来监测细胞的种群密度。在海洋弧菌物种中，哈氏弧菌型LuxR蛋白是群体感应磷酸化级联反应中的关键参与者，其控制毒力、共生和存活基因的表达。以前，我们的特点是鳗弧菌同系物的LuxR（VanT）和LuxMN（VanMN），在这项研究中，我们已经确定了同系物的LuxPQ（VanPQ）和Luxlaughus（Vanalaughus）。与其他弧菌物种相比，vanT在低细胞密度下表达，并且随着细胞数量的增加没有显示出显著的诱导。此外，尽管VanO的缺失增加了vanT的表达，但VanU的缺失却意外地降低了vanT的表达。即使在vanU突变体中，VanN和VanQ也是抑制vanT所需的，这表明VanNQ信号转导的另一种途径，而不是通过VanU。VanT通过结合和抑制vanT启动子以及通过结合和激活vanT启动子来负调节其自身的表达。信号中继导致细胞应答，因为金属蛋白酶empA的表达在所有突变体中与vanT的表达类似地改变。因此，鳗弧菌群体感应磷酸化系统的工作方式与哈维氏弧菌不同，可用于限制而不是诱导vanT表达。
Many bacterial cells communicate using diffusible signal molecules to monitor cell population density via a process termed quorum sensing. In marine Vibrio species, the Vibrio harveyi-type LuxR protein is a key player in a quorum-sensing phosphorelay cascade, which controls the expression of virulence, symbiotic and survival genes. Previously, we characterized Vibrio anguillarum homologues of LuxR (VanT) and LuxMN (VanMN) and, in this study, we have identified homologues of LuxPQ (VanPQ) and LuxOU (VanOU). In contrast to other Vibrio species, vanT was expressed at low cell density and showed no significant induction as the cell number increased. In addition, although the loss of VanO increased vanT expression, the loss of VanU, unexpectedly, decreased it. Both VanN and VanQ were required for repression of vanT even in a vanU mutant, suggesting an alternative route for VanNQ signal transduction other than via VanU. VanT negatively regulated its own expression by binding and repressing the vanT promoter and by binding and activating the vanOU promoter. The signal relay results in a cellular response as expression of the metalloprotease, empA, was altered similar to that of vanT in all the mutants. Consequently, the V. anguillarum quorum-sensing phosphorelay systems work differently from those of V. harveyi and may be used to limit rather than induce vanT expression.