Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors
Revisiting the quorum-sensing hierarchy in Pseudomonas aeruginosa: the transcriptional regulator RhlR regulates LasR-specific factors
复制标题
DOI：
10.1099/mic.0.022764-0
复制
发表时间：
2009-03-01
期刊：
影响因子：
2.8
通讯作者：
Deziel, Eric
中科院分区：
文献类型：
--
作者：
Dekimpe, Valerie;Deziel, Eric
铜绿假单胞菌使用两个主要的群体感应（OS）调节系统las和rhl来调节其许多毒力因子的表达。劳工会计制度被认为是QS体系的最高层。然而，一些毒力因子，如绿脓菌素已被报道在某些条件下仍然产生lasR突变体。有趣的是，这些突变体在各种条件下自发出现，包括囊性纤维化患者的气道。使用转录lacZ报告，LC/MS定量和表型分析，我们已经调查了由LAS系统的OS控制的因素的调节。我们的研究结果表明，活性的rhl系统仅延迟在lasR突变体，从而允许多个毒力决定因素，如绿脓菌素，鼠李糖脂和C-4-高丝氨酸内酯（HSL）在后期稳定期的表达。此外，在这个阶段，RhIR能够通过激活特定的LasR控制的功能，包括3-氧代-C-12-HSL和假单胞菌喹诺酮信号（PQS）的产生，克服las系统的缺失。因此，铜绿假单胞菌能够通过允许另一个接管来规避其QS系统之一的缺陷。这项工作表明，QS层次结构比简单地将las系统呈现在rhl系统之上的模型更复杂。
Pseudomonas aeruginosa uses the two major quorum-sensing (OS) regulatory systems las and rhl to modulate the expression of many of its virulence factors. The las system is considered to stand at the top of the QS hierarchy. However, some virulence factors such as pyocyanin have been reported to still be produced in lasR mutants under certain conditions. Interestingly, such mutants arise spontaneously under various conditions, including in the airways of cystic fibrosis patients. Using transcriptional lacZ reporters, LC/MS quantification and phenotypic assays, we have investigated the regulation of OS-controlled factors by the las system. Our results show that activity of the rhl system is only delayed in a lasR mutant, thus allowing the expression of multiple virulence determinants such as pyocyanin, rhamnolipids and C-4-homoserine lactone (HSL) during the late stationary phase. Moreover, at this stage, RhIR is able to overcome the absence of the las system by activating specific LasR-controlled functions, including production of 3-oxo-C-12-HSL and Pseudomonas quinolone signal (PQS). P. aeruginosa is thus able to circumvent the deficiency of one of its QS systems by allowing the other to take over. This work demonstrates that the QS hierarchy is more complex than the model simply presenting the las system above the rhl system.