RsaL, a novel repressor of virulence gene expression in Pseudomonas aeruginosa
RsaL, a novel repressor of virulence gene expression in Pseudomonas aeruginosa
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DOI：
10.1128/jb.181.7.2175-2184.1999
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发表时间：
1999-04-01
影响因子：
3.2
通讯作者：
Iglewski, BH
中科院分区：
文献类型：
--
作者：
De Kievit, T;Seed, PC;Iglewski, BH
作为铜绿假单胞菌群体感应系统的组成部分，LasR 和 PAT-I 全局调节多个毒力决定簇以及第二个铜绿假单胞菌群体感应系统的表达。迄今为止，尚无关于铜绿假单胞菌群体感应级联负调节的信息。在这里，我们描述了一个新基因 rsaL，它位于 lasR 下游，并相对于 lasR 转录反义。在铜绿假单胞菌中，rsaL 的过度表达会导致 lasB 表达减少和弹性蛋白酶活性降低。通过使用 6-His 蛋白融合系统，我们证明 rsaL 编码 11-kDa 蛋白。利用携带 lacZ 转录融合的大肠杆菌 lambda 溶原菌对培养物中的 PAI-1 水平进行直接定量和研究表明，RsaL 特异性抑制 PAI-1 自诱导剂合酶基因的转录，lasI RsaL 对 lasI 的抑制作用以及相关的弹性蛋白酶活性降低对所有 LasR-PAI-1 依赖性毒力基因的表达和 P.铜绿假单胞菌。
As components of a Pseudomonas aeruginosa quorum-sensing system, LasR and PAT-I globally regulate expression of multiple virulence determinants, as well as the second P. aeruginosa quorum-sensing system. To date, no information exists on negative regulation of the quorum-sensing cascade in P. aeruginosa. Here we describe a novel gene, rsaL, which is located downstream from lasR and transcribed antisense relative to lasR. In P. aeruginosa, overexpression of rsaL results in reduced lasB expression and decreased elastase activity. With the use of a six-His protein fusion system, we demonstrate that rsaL encodes an 11-kDa protein. Direct quantitation of PAI-1 levels in cultures and studies utilizing Escherichia coli lambda lysogens carrying lacZ transcriptional fusions reveal that RsaL specifically represses transcription of the PAI-1 autoinducer synthase gene, lasI RsaL's repressive effect on lasI and the associated decrease in elastase activity have important implications for the expression of all LasR-PAI-1-dependent virulence genes and the overall pathogenicity of P. aeruginosa.