The global regulator Crc plays a multifaceted role in modulation of type III secretion system in Pseudomonas aeruginosa
Article first published online: 4 JAN 2013
© 2012 The Authors. MicrobiologyOpen published by Blackwell Publishing Ltd.
This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Volume 2, Issue 1, pages 161–172, February 2013
How to Cite
MicrobiologyOpen 2013; 2(1): 161–172
- Issue published online: 13 FEB 2013
- Article first published online: 4 JAN 2013
- Manuscript Accepted: 5 NOV 2012
- Manuscript Revised: 29 OCT 2012
- Manuscript Received: 6 SEP 2012
- Crc ;
- exsA ;
- Pseudomonas aeruginosa ;
- type III secretion system
The opportunistic pathogen Pseudomonas aeruginosa utilizes type III secretion system (T3SS) to translocate effector proteins into eukaryotic host cells that subvert normal host cell functions to the benefit of the pathogen, and results in serious infections. T3SS in P. aeruginosa is controlled by a complex system of regulatory mechanisms and signaling pathways. In this study, we described that Crc, an RNA-binding protein, exerts a positive impact on T3SS in P. aeruginosa, as evidenced by promoter activity assays of several key T3SS genes, transcriptomics, RT-PCR, and immunoblotting in crc mutant. We further demonstrated that the regulatory function of Crc on the T3SS was mediated through the T3SS master regulator ExsA and linked to the Cbr/Crc signaling system. Expression profiling of the crc mutant revealed a downregulation of flagship T3SS genes as well as 16 other genes known to regulate T3SS gene expression in P. aeruginosa. On the basis of these data, we proposed that Crc may exert multifaceted control on the T3SS through various pathways, which may serve to fine-tune this virulence mechanism in response to environmental changes and nutrient sources.