Intercellular Signaling in Vibrio harveyi

这项研究的长期目标是探索细菌用于细胞间通讯的分子机制。该建议的重点是在模式生物发光海洋细菌哈维氏弧菌的群体感应的研究。哈维氏弧菌有两个群体感应回路（信号系统1和信号系统2），它们会聚以调节光的产生（Lux）。每个系统由双组分传感器-自动感应器对组成;系统1的LuxN/AI-1和系统2的LuxQ/AI-2。两种传感器都将信息传递给一种名为LuxU的共享磷酸化蛋白，后者又将信号传递给反应调节蛋白LuxO。Phospho-LuxO间接地负责在低细胞密度下抑制荧光素酶的产生，因为它激活Lux的负调节因子的表达。称为LuxR的转录激活蛋白也是表达荧光素酶结构操纵子所必需的。结果表明，哈维氏弧菌利用信号系统1和AI-1进行种内通讯，利用信号系统2和AI-2进行种间通讯。LuxO和RpoN是在低细胞密度下抑制发光表达所必需的。这两种蛋白质都是在低细胞密度下激活阻遏物X所需的假设将通过分离和表征推定阻遏物基因中的突变来测试。

The long term goal of this research is to explore the molecular mechanisms that bacteria use for inter-cellular communication. This proposal focuses on a study of quorum sensing in the model bioluminescent marine bacterium Vibrio harveyi. V. harveyi has two quorum sensing circuits (Signalling System 1 and Signaling System 2) that converge to regulate light production (Lux). Each system is made up of a two-component sensor-autoinducer pair; LuxN/AI-1 for System 1 and LuxQ/AI-2 for System 2. Both sensors transduce information to a shared phosphorelay protein called LuxU, which in turn conveys the signal to the response regulator protein LuxO. Phospho-LuxO is indirectly responsible for repression of luciferase production at low cell density, because it activates the expression of a negative regulator of Lux. A transcriptional activator protein called LuxR is also required for expression of the luciferase structural operon. Results suggest that V. harveyi uses Signaling System 1 and AI-1 for intra-species communication and Signaling System 2 and AI-2 for inter-species communication. LuxO and RpoN are required for the repression of the expression of luminescence at low cell density. The hypothesis that both of these proteins are required for the activation of a repressor X at low cell density will be tested by isolating and characterizing mutations in the putative repressor gene.