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首页> 外文期刊>Journal of bacteriology >Inhibition of Quorum Sensing by a Pseudomonas aeruginosa dksA Homologue
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Inhibition of Quorum Sensing by a Pseudomonas aeruginosa dksA Homologue

机译:铜绿假单胞菌dksA同源物对群体感应的抑制作用

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The Pseudomonas aeruginosa las (lasR-lasI) andrhl (rhlR-rhlI) quorum-sensing systems regulate the expression of several virulence factors, including elastase and rhamnolipid. P. aeruginosa strain PR1-E4 is alasR deletion mutant that contains a second, undefined mutation which allows production of elastase and rhamnolipid despite a nonfunctional las system. We have previously shown that this strain accomplishes this by increasing the expression of the autoinducer synthase gene rhlI. In this report, we show that the elastolytic phenotype of mutant PR1-E4 can be complemented with a P. aeruginosa homologue of the Escherichia coli dnaK mutation suppressor gene dksA. When supplied in trans on a multicopy plasmid, this gene completely suppressed elastase production by mutant PR1-E4. Cloning and Northern blot analysis revealed that dksA was neither mutated nor less transcribed in mutant PR1-E4. When overexpressed,dksA also reduced rhamnolipid production by both mutant PR1-E4 and the wild type, PAO1. Using Northern blot analysis andlacZ reporter fusions, we show that dksAinhibits rhlI, rhlAB, and lasB transcription. Exogenous N-butyryl–l-homoserine lactone overcame the reduced expression of rhlI and restoredrhlAB and lasB expression, as well as elastase production. Our results suggest that the overproduction of the P. aeruginosa DksA homologue inhibits quorum-sensing-dependent virulence factor production by downregulating the transcription of the autoinducer synthase gene rhlI.
机译:铜绿假单胞菌(lasR-lasI )和 rhl(rhlR-rhlI )群体感应系统调节几种毒力因子的表达,包括弹性蛋白酶和鼠李糖脂。 P。铜绿假单胞菌PR1-E4是一个 lasR 缺失突变体,它包含第二个不确定的突变,尽管该系统没有功能,但仍可以产生弹性蛋白酶和鼠李糖脂。先前我们已经表明,该菌株可通过增加自诱导合成酶基因 rhlI 的表达来实现这一目的。在此报告中,我们显示了突变体PR1-E4的弹性表型可以与 P互补。大肠杆菌dnaK突变抑制基因dksA的铜绿假单胞菌的同源物。当以 trans 形式提供给多拷贝质粒时,该基因完全抑制了突变体PR1-E4产生的弹性蛋白酶。克隆和Northern印迹分析表明 dksA 在突变体PR1-E4中既没有突变也没有转录。当过表达时, dksA 也会减少突变体PR1-E4和野生型PAO1鼠李糖脂的产生。使用Northern印迹分析和 lacZ 报告基因融合,我们显示 dksA 抑制 rhlI,rhlAB lasB 转录。外源的 N -丁酰基-1-高丝氨酸内酯克服了 rhlI 的表达降低,恢复了 rhlAB lasB 的表达,以及弹性蛋白酶的生产。我们的结果表明 P的生产过剩。铜绿假单胞菌DksA同源物通过下调自诱导合成酶基因 rhlI 的转录来抑制群体感应依赖性毒力因子的产生。

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