Transcription of exsD is repressed directly by H-NS in Vibrio parahaemolyticus

• Published in: Microbial pathogenesis 2016-08, Vol.97, p.221-225
• Main Authors: Zhang, Yiquan, Osei-Adjei, George, Ni, Bin, Fang, Haihong, Zhang, Lingyu, Zhao, Xin, Huang, Xinxiang, Yang, Huiying, Yang, Wenhui, Sun, Fengjun
• Format: Article
• Language: English
• Subjects: Artificial Gene Fusion; Bacterial Proteins - metabolism; beta-Galactosidase - analysis; beta-Galactosidase - genetics; DNA Footprinting; DNA-Binding Proteins - metabolism; Electrophoretic Mobility Shift Assay; exsD; Gene Expression Profiling; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genes, Regulator; H-NS; Membrane Proteins - biosynthesis; Membrane Proteins - genetics; Real-Time Polymerase Chain Reaction; T3SS1; Transcription Initiation Site; Transcription, Genetic; Vibrio parahaemolyticus; Vibrio parahaemolyticus - genetics; Vibrio parahaemolyticus - metabolism
• ISSN: 0882-4010; 1096-1208
• DOI: 10.1016/j.micpath.2016.06.003

Vibrio parahaemolyticus is a leading cause of seafood-associated diarrhea and gastroenteritis. This bacteria expresses a major virulence determinant called T3SS1. Expression of T3SS1 is tightly regulated by the ExsA-ExsC-ExsD regulatory system. The transcription of exsA and probably exsC is repressed directly by the H-NS protein. In this study, the regulation of exsD by H-NS was investigated using quantitative RT-PCR, primer extension, LacZ fusion, electrophoretic mobility shift, and DNase I footprinting assays. The results showed that His-H-NS protected a single region from 61 bp to 174 bp upstream of exsD against DNase I digestion, and a transcription start site located at 105 bp upstream of exsD was detected and its activity was repressed by H-NS. Therefore, a single H-NS-dependent promoter was transcribed for exsD in V. parahaemolyticus. Thus, all three genes in the ExsA-ExsC-ExsD regulatory system of T3SS1 are directly repressed by H-NS in V. parahaemolyticus.