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The Scientific World Journal
Volume 2012, Article ID 982140, 7 pages
Research Article

Expression of the Type VI Secretion System 1 Component Hcp1 Is Indirectly Repressed by OpaR in Vibrio parahaemolyticus

1Department of Emergency Medicine, General Hospital of Chinese People's Armed Police Forces, Beijing 100039, China
2State Key Laboratory of Pathogen and Biosecurity, Beijing Institute of Microbiology and Epidemiology, Beijing 100071, China
3School of Public Health, Chongqing Medical University, Chongqing 400016, China

Received 21 March 2012; Accepted 7 May 2012

Academic Editors: M. L. Arbonés, V. E. Fernandez Pinto, J. Qiu, and P. Webster

Copyright © 2012 Lizhi Ma et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The type VI secretion system (T6SS) is bacterial protein injection machinery with roles in virulence, symbiosis, interbacterial interaction, antipathogenesis, and environmental stress responses. There are two T6SS loci, T6SS1 and T6SS2, in the two chromosomes of Vibrio parahaemolyticus, respectively. This work disclosed that the master quorum sensing (QS) regulator OpaR repressed the transcription of hcp1 encoding the structural component Hcp1 of T6SS1 in V. parahaemolyticus, indicating that QS had a negative regulatory action on T6SS1. A single 𝜎 5 4 -dependent promoter was transcribed for hcp1 in V. parahaemolyticus, and its activity was repressed by the OpaR regulator. Since the OpaR protein could not bind to the upstream region of hcp1, OpaR would repress the transcription of hcp1 in an indirect manner.