The RssB/RssA two-component system regulates biosynthesis of the tripyrrole antibiotic, prodigiosin, in Serratia marcescens
The RssB/RssA two-component system regulates biosynthesis of the tripyrrole antibiotic, prodigiosin, in Serratia marcescens
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DOI：
10.1016/j.ijmm.2010.01.003
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发表时间：
2010-06-01
影响因子：
4.1
通讯作者：
Soo, Po-Chi
中科院分区：
文献类型：
--
作者：
Horng, Yu-Tze;Chang, Kai-Chih;Soo, Po-Chi
粘质沙雷氏菌CH-1产生一种红色的细胞相关色素灵菌红素，由猪操纵子中编码的酶合成。潜在的调节机制，特别是其与RssAB双组分系统信号传导的关系，仍然没有表征。在这里，我们表明，磷酸化的RssB（RssB-P）直接结合到猪操纵子（pigA启动子）的启动子区域，如使用电泳迁移率变动分析所观察到的。此外，我们确定RssB-P结合位点位于下游的-10和-35区域的pigA使用DNA酶I足迹分析。flhDC、rss B和pigA启动子区域中RssB-P结合位点的汇编揭示了保守核心序列GAGATTITAGCTAAATTAATBTTT（B=C、G或T）的存在，我们认为其是Rss B结合序列。pigA启动子区域中的保守RssB结合序列内的保守核苷酸的位点特异性突变导致在体外存在RssB-P的情况下不存在阻滞和体内pigA的转录升高。这些数据表明，RssAB信号负调控灵菌红素的生产，这种抑制是通过直接和特异性抑制猪操纵子的转录活性介导的。(C)2010年Elsevier GmbH。All rights reserved.
Serratia marcescens CH-1 produces a red, cell-associated pigment, prodigiosin, synthesized by enzymes encoded in the pig operon. The underlying regulatory mechanism, especially its relationship with the RssAB two-component system signaling, remained uncharacterized. Here, we show that phosphorylated RssB (RssB-P) directly binds to the promoter region of the pig operon (pigA promoter), as observed using an electrophoretic mobility shift assay. Furthermore, we identify the RssB-P binding site located downstream of the -10 and -35 regions in pigA using a DNase I footprinting assay. A compilation of the RssB-P binding sites in flhDC, rssB and pigA promoter regions reveals the presence of a conserved core sequence, GAGATTITAGCTAAATTAATBTTT (B=C, G, or T), which we believe is the RssB binding sequence. Site-specific mutation of conserved nucleotides within the conserved RssB binding sequence in the pigA promoter region leads to absence of retardation in the presence of RssB-P in vitro and elevated transcription of pigA in vivo. These data suggest that RssAB signaling negatively regulates prodigiosin production, and such inhibition is mediated through direct and specific repression of transcriptional activity of the pig operon. (C) 2010 Elsevier GmbH. All rights reserved.