Indole induces the expression of multidrug exporter genes in Escherichia coli
Indole induces the expression of multidrug exporter genes in Escherichia coli
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DOI：
10.1111/j.1365-2958.2004.04449.x
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发表时间：
2005-02-01
影响因子：
3.6
通讯作者：
Yamaguchi, A
中科院分区：
文献类型：
--
作者：
Hirakawa, H;Inazumi, Y;Yamaguchi, A
我们的全面表达克隆研究先前显示，20个内在的异生物质输出系统编码的大肠杆菌染色体，但他们中的大多数在正常条件下不表达。在这项研究中，我们研究了诱导这些异源生物质输出基因表达的化合物，发现吲哚诱导多种异源生物质输出基因，包括acrD，acrE，cusB，emrK，mdtA，mdtE和yceL。吲哚处理E. coli细胞分别通过诱导mdtEF和acrD基因表达来赋予罗丹明6G和SDS抗性。吲哚对mdtE的诱导不依赖于调节mdtE基因的EvgSA双组分信号转导系统，而是由GadX介导。另一方面，acrD和mdtA的诱导由BaeSR和CpxAR双组分系统介导。有趣的是，CpxAR系统介导的诱导需要内在的baeSR基因，而在cpxAR基因缺失突变体中观察到BaeSR介导的诱导。BaeR和CpxR直接与acrD和mdtA启动子区的不同序列结合。这些观察结果表明，BaeR是一个主要的调节器，CpxR增强BaeR的效果。
Our comprehensive expression cloning studies previously revealed that 20 intrinsic xenobiotic exporter systems are encoded in the Escherichia coli chromosome, but most of them are not expressed under normal conditions. In this study, we investigated the compounds that induce the expression of these xenobiotic exporter genes, and found that indole induces a variety of xenobiotic exporter genes including acrD, acrE, cusB, emrK, mdtA, mdtE and yceL. Indole treatment of E. coli cells confers rhodamine 6G and SDS resistance through the induction of mdtEF and acrD gene expression respectively. The induction of mdtE by indole is independent of the EvgSA two-component signal transduction system that regulates the mdtE gene, but mediated by GadX. On the other hand, the induction of acrD and mdtA was mediated by BaeSR and CpxAR, two-component systems. Interestingly, CpxAR system-mediated induction required intrinsic baeSR genes, whereas BaeSR-mediated induction was observed in the cpxAR gene-deletion mutant. BaeR and CpxR directly bound to different sequences of the acrD and mdtA promoter regions. These observations indicate that BaeR is a primary regulator, and CpxR enhances the effect of BaeR.