The long-chain fatty acid sensor, PsrA, modulates the expression of rpoS and the type III secretion exsCEBA operon in Pseudomonas aeruginosa.
The long-chain fatty acid sensor, PsrA, modulates the expression of rpoS and the type III secretion exsCEBA operon in Pseudomonas aeruginosa.
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DOI：
10.1111/j.1365-2958.2009.06757.x
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发表时间：
2009-07
影响因子：
3.6
通讯作者：
Hoang TT
中科院分区：
文献类型：
--
作者：
Kang Y;Lunin VV;Skarina T;Savchenko A;Schurr MJ;Hoang TT
铜绿假单胞菌PsrA自身阻遏物具有双重作用，作为fadBA 5 β-氧化操纵子的阻遏物和III型分泌系统（TTSS）的静止相σ因子rpoS和exsCEBA-操纵子的激活物。以前，我们证明了PsrA对fadBA 5操纵子的抑制被长链脂肪酸（LCFA）缓解。然而，影响通过PsrA激活rpoS和exsC的信号是未知的。在这项研究中，微阵列和基因融合数据表明，LCFA（如油酸）影响rpoS和exsC的表达。DNA结合研究证实PsrA结合到rpoS和exsC启动子区域。这种结合被LCFA抑制，表明LCFA通过PsrA直接影响这两个基因的激活。LCFA降低rpoS和exsC表达，分别导致N-（丁酰基）-l-高丝氨酸-内酯群体感应信号增加和ExoS/T产生减少。基于PsrA的晶体结构，在被认为容纳LCFA的疏水通道内的氨基酸残基的定点诱变产生了两个LCFA非响应性PsrA突变体。LCFA不再抑制这些PsrA突变体对rpoS和exsC的结合和激活。这些数据支持了一个机制模型，其中LCFA影响PsrA调节以控制铜绿假单胞菌中的LCFA代谢和一些毒力基因。
The Pseudomonas aeruginosa PsrA autorepressor has dual roles as a repressor of the fadBA5 β-oxidation-operon and an activator of the stationary-phase sigma factor rpoS and exsCEBA-operon of the type III secretion system (TTSS). Previously, we demonstrated that the repression of the fadBA5-operon by PsrA is relieved by long-chain fatty acids (LCFA). However, the signal affecting the activation of rpoS and exsC via PsrA is unknown. In this study, microarray and gene-fusion data suggested that LCFA (e.g. oleate) affected the expression of rpoS and exsC. DNA binding studies confirmed that PsrA binds to the rpoS and exsC promoter regions. This binding was inhibited by LCFA, indicating that LCFA directly affects the activation of these two genes through PsrA. LCFA decreased rpoS and exsC expression, resulting in increased N-(butyryl)-l-homoserine-lactone quorum-sensing signal and decreased ExoS/T production, respectively. Based on the crystal structure of PsrA, site-directed mutagenesis of amino acid residues, within the hydrophobic channel thought to accommodate LCFA, created two LCFA-nonresponsive PsrA mutants. The binding and activation of rpoS and exsC by these PsrA mutants was no longer inhibited by LCFA. These data support a mechanistic model where LCFA influence PsrA regulation to control LCFA metabolism and some virulence genes in P. aeruginosa.
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DOI：
10.1107/s0907444904019158
发表时间：
2004-12-01
影响因子：
2.2
作者：
Emsley, P;Cowtan, K
通讯作者：
Cowtan, K
影响因子：
2.2
作者：
Abd, Hadi;Wretlind, Bengt;Sandstrom, Gunnar
通讯作者：
Sandstrom, Gunnar
影响因子：
3.2
作者：
O'Toole, GA;Gibbs, KA;Kolter, R
通讯作者：
Kolter, R
影响因子：
2.6
作者：
Hoang, TT;Kutchma, AJ;Schweizer, HP
通讯作者：
Schweizer, HP
影响因子：
3.6
作者：
FinckBarbancon, V;Goranson, J;Frank, DW
通讯作者：
Frank, DW