Induction of the mtrCDE-encoded efflux pump system of Neisseria gonorrhoeae requires MtrA, an AraC-like protein
Induction of the mtrCDE-encoded efflux pump system of Neisseria gonorrhoeae requires MtrA, an AraC-like protein
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DOI：
10.1046/j.1365-2958.1999.01517.x
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发表时间：
1999-08-01
影响因子：
3.6
通讯作者：
Shafer, WM
中科院分区：
文献类型：
--
作者：
Rouquette, C;Harmon, JB;Shafer, WM
淋球菌中的mtr（多重可转移耐药）基因复合物编码由MtrC-MtrD-MtrE细胞包膜蛋白组成的能量依赖性外排泵，其用于输出结构多样的抗微生物疏水剂（HA）。这些试剂中的许多具有膜作用去污剂活性。使用Triton X-100（TX-100）作为代表性HA，我们发现，当HA敏感菌株暴露于亚致死浓度的这种非离子去污剂和结构相关的杀精剂壬苯醇醚-9时，mtrCDE外排泵操纵子可以被诱导至更高水平的表达。这种诱导是在mtrCDE基因转录的水平上，并且不依赖于通常降低mtrCDE基因表达的MtrR阻遏物。然而，淋球菌对TX-100的增强的抗性依赖于先前未描述的淋球菌蛋白的表达，所述淋球菌蛋白属于转录激活因子的AraC/XylS家族。我们将这种蛋白质称为MtrA，以表示其在mtrCDE基因表达激活中的可能作用。与以前的研究一起处理的mtrCDE基因表达的遗传控制，我们建议淋球菌可以通过正向和负向转录控制过程来调节它们对HA的抗性。这些调节过程的作用可能是重要的，在确定淋球菌的生存能力在粘膜表面含有洗涤剂样HA。
The mtr(multiple transferable resistance) gene complex in Neisseria gonorrhoeae encodes an energy-dependent efflux pump composed of the MtrC-MtrD-MtrE cell envelope proteins that serves to export structurally diverse antimicrobial, hydrophobic agents (HAs). Many of these agents have membrane-acting detergent activity. Using Triton X-100 (TX-100) as a representative HA, we found that the mtrCDE efflux pump operon could be induced to higher levers of expression when an HA-sensitive strain was exposed to sublethal concentrations of this non-ionic detergent and the structurally related spermicide, nonoxynol-9. This induction was at the level of mtrCDE gene transcription and was independent of the MtrR repressor, which normally decreases mtrCDE gene expression. However, the enhanced resistance of gonococci to TX-100 was dependent on the expression of a previously undescribed gonococcal protein that belonged to the AraC/XylS family of transcriptional activators. We have termed this protein MtrA to signify its likely role in the activation of mtrCDE gene expression. Taken together with previous studies dealing with the genetic control of mtrCDE gene expression, we propose that gonococci can modulate their resistance to HAs through both positive and negative transcriptional control processes. The action of these regulatory processes is probably of importance in determining the survival capacity of gonococci at mucosal surfaces that contain detergent-like HAs.