The Pseudomonas aeruginosa Global Regulator VqsR Directly Inhibits QscR To Control Quorum-Sensing and Virulence Gene Expression
The Pseudomonas aeruginosa Global Regulator VqsR Directly Inhibits QscR To Control Quorum-Sensing and Virulence Gene Expression
复制标题
铜绿假单胞菌全局调节因子 VqsR 直接抑制 QscR 来控制群体感应和毒力基因表达
DOI：
10.1128/jb.06679-11
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发表时间：
2012-06-01
影响因子：
3.2
通讯作者：
He, Chuan
中科院分区：
文献类型：
--
作者：
Liang, Haihua;Deng, Xin;He, Chuan
摘要机会致病菌铜绿假单胞菌至少有三个群体感应（QS）系统，包括酰基高丝氨酸内酯（acyl-HSL）介导的las和rhl系统，以及基于2-烷基-4（1H）-喹诺酮（AHQ）信号的系统。已经确定了这些QS系统的一组关键调节器，如qteE、vqsM、vqsR和vfr。然而，这些质量体系的基本监管机制尚未完全了解。在这里，使用电泳迁移率变动分析，我们证明，VqsR间接调节酰基-HSL系统，但特异性结合到qscR启动子区，这表明VqsR通过QscR影响QS控制的途径。通过基于染料的DNA酶I足迹分析，我们表明VqsR与qscR启动子区域中的反向重复（IR）基序（TCGCCN 8 GGCGA，其中N是任何核苷酸）相互作用。全基因组搜索确定了50个其他启动子区域携带相同的推定IR基序。重组VqsR蛋白在溶液中作为同源二聚体存在。此外，使用qscR-lux报告基因测定和北方印迹杂交，我们发现，与野生型PAO 1菌株相比，vqsR缺失菌株中qscR的转录水平增加了4倍，表明vqsR是qscR的负调节因子。总之，这些发现为铜绿假单胞菌QS系统的复杂调控网络提供了新的见解。
ABSTRACT The opportunistic pathogen Pseudomonas aeruginosa has at least three quorum-sensing (QS) systems, including the acyl-homoserine lactone (acyl-HSL)-mediated las and rhl systems, as well as the 2-alkyl-4(1H)-quinolone (AHQ) signal-based system. A group of key regulators of these QS systems have been identified, such as qteE, vqsM, vqsR, and vfr. However, the underlying regulatory mechanisms of these QS systems are not yet fully understood. Here, using electrophoretic mobility shift assays, we demonstrated that VqsR indirectly regulates acyl-HSL systems but specifically binds to the qscR promoter region, which indicates that VqsR influences QS-controlled pathways through QscR. Through a dye-based DNase I footprint assay, we showed that VqsR interacts with an inverted repeat (IR) motif (TCGCCN8GGCGA, where N is any nucleotide) in the promoter region of qscR. A genome-wide search identified 50 other promoter regions carrying the same putative IR motif. The recombinant VqsR protein exists as a homodimer in solution. In addition, using a qscR-lux reporter assay and Northern blot hybridization, we found that the transcription level of qscR increased 4-fold in the vqsR deletion strain compared to the wild-type PAO1 strain, indicating vqsR as a negative regulator of qscR. Taken together, these findings provide new insights into the complex regulation network of QS systems in P. aeruginosa.