A genetic analysis of the function of LuxO, a two-component response regulator involved in quorum sensing in Vibrio harveyi
A genetic analysis of the function of LuxO, a two-component response regulator involved in quorum sensing in Vibrio harveyi
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DOI：
10.1046/j.1365-2958.1999.01208.x
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发表时间：
1999-01-01
影响因子：
3.6
通讯作者：
Bassler, BL
中科院分区：
文献类型：
--
作者：
Freeman, JA;Bassler, BL
两个独立的群体感应系统控制着海洋细菌哈维氏弧菌的生物发光(Lux)的表达，每个系统由一个自身诱导子(Al-1或Al-2)及其同源感受器(LuxN或LuxQ)组成，传感器是双组分的杂交蛋白，既含有传感器激酶结构域，又含有反应调节结构域。来自这两个系统的感觉信息通过磷酸转移机制传递到共享的整合蛋白LUXO，LUXO是双组分信号转导蛋白家族中反应调节类的成员，LUXO负向控制发光。在这篇报道中，我们在Luxo中构建了错义突变和帧内缺失突变，这些突变编码了模拟磷酸化或非磷酸化形式的蛋白质，并将这些突变引入到位于Luxo基因座的哈维氏弧菌染色体中。对产生的突变株V，harveyi的表型分析表明，Luxo的磷酸化形式是阻遏蛋白，而非磷酸化形式的蛋白是非活性的。对含有单、双LuxN和LuxQ突变的哈维氏弧菌的lux表型分析表明，LuxN和Luxo对Luxo具有两种活性。在没有自身诱导剂的情况下，它们在低细胞密度时扮演Luxo蛋白激酶的角色，在存在自身诱导剂的情况下，它们在高细胞密度时转换为Luxo蛋白磷酸酶。此外，来自两个系统的输入对群体感应的调节的时间和效力是不同的。
Two independent quorum-sensing systems control the expression of bioluminescence (lux) in the marine bacterium Vibrio harveyi, Each system is composed of an autoinducer(Al-1 or Al-2) and its cognate sensor (LuxN or LuxQ), The sensors are two-component hybrid kinases, containing both sensor kinase domains and response regulator domains. Sensory information from the two systems is relayed by a phosphotransfer mechanism to a shared integrator protein called LuxO, LuxO is a member of the response regulator class of the two-component family of signal transduction proteins, and LuxO acts negatively to control luminescence. In this report, missense and in frame deletion mutations were constructed in luxO that encoded proteins mimicking either the phosphorylated or the unphosphorylated form, and these mutations were introduced into the V. harveyi chromosome at the luxO locus. Phenotypical analyses of the resulting mutant V, harveyi strains indicate that the phosphorylated form of LuxO is the repressor, and that the unphosphorylated form of the protein is inactive, Analysis of the lux phenotypes of V. harveyi strains containing single and double luxN and luxQ mutations indicate that LuxN and LuxO have two activities on LuxO. They act as LuxO protein kinases at low cell density in the absence of autoinducers, and they switch to LuxO protein phosphatases at high cell density in the presence of autoinducers. Furthermore, the timing and potency of inputs from the two systems into regulation of quorum sensing are different.