Bioluminescence in Vibrio fischeri is controlled by the redox-responsive regulator ArcA
Bioluminescence in Vibrio fischeri is controlled by the redox-responsive regulator ArcA
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DOI：
10.1111/j.1365-2958.2007.05809.x
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发表时间：
2007-07-01
影响因子：
3.6
通讯作者：
Stabb, Eric V.
中科院分区：
文献类型：
--
作者：
Bose, Jeffrey L.;Kim, Unmi;Stabb, Eric V.
由费氏弧菌Lux系统产生的生物发光消耗氧气和还原功率，有人提出细胞利用这一点来抵消氧化应激或过量还原剂的积累。这些模型预测Lux的表达应该对氧化还原条件做出反应；然而，目前还不知道Lux的氧化还原响应调节因子。我们发现，负责生物发光的LuxiCDABEG操纵子受到ArcAB系统的抑制，该系统在还原条件下被激活。与ArcAB在氧化还原监测和Lux调节之间的作用一致，添加还原剂以一种弧形依赖的方式减少发光。Arca与LuxlCDABEG启动子结合并调节其转录，并抑制明亮菌株MJ1和ES114的发光，ES114是从鱿鱼真鼻虫头节分离出来的，在培养中不明显发光。在ES114中，删除ArcA使培养中的发光增加了约500倍，达到与共生细胞相当的可见水平。ArcA不能抑制共生发光，但在接种后48h，ArcA确实对定殖竞争力有贡献。我们假设，在最初的定植过程中，Arca对氧化应激的失活会降低LuxlCDABEG的表达，但ArcAB在既定感染的更少的环境中积极调节其他代谢途径。
Bioluminescence generated by the Vibrio fischeri Lux system consumes oxygen and reducing power, and it has been proposed that cells use this to counteract either oxidative stress or the accumulation of excess reductant. These models predict that lux expression should respond to redox conditions; yet no redoxresponsive regulator of lux is known. We found that the luxiCDABEG operon responsible for bioluminescence is repressed by the ArcAB system, which is activated under reducing conditions. Consistent with a role for ArcAB in connecting redox monitoring to lux regulation, adding reductant decreased luminescence in an arc-dependent manner. ArcA binds to and regulates transcription from the luxlCDABEG promoter, and it represses luminescence both in the bright strain MJ1 and in ES114, an isolate from the squid Euprymna scolopes that is not visibly luminescent in culture. In ES114, deleting arcA increased luminescence in culture similar to 500-fold to visible levels comparable to that of symbiotic cells. ArcA did not repress symbiotic luminescence, but by 48 h after inoculation, ArcA did contribute to colonization competitiveness. We hypothesize that inactivation of ArcA in response to oxidative stress during initial colonization derepresses luxlCDABEG, but that ArcAB actively regulates other metabolic pathways in the more reduced environment of an established infection.