Positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis.
OmpR has been demonstrated to negatively regulate the expression of the flagellar master operon flhDC in a wide variety of bacterial species. Here we report the positive regulation of flhDC expression by OmpR in Yersinia pseudotuberculosis. A sigma(70)-dependent promoter was identified by primer extension analysis and an active region with two conserved OmpR-binding sites around the flhDC promoter was confirmed. To confirm the regulation of flhDC expression by OmpR, flhDC as well as the downstream flagellar genes fliA, flgD, flgA, flgM, fliC and flaA were fused to lacZ, and decreased expression of all these genes in an ompR mutant (Delta ompR) was detected. Furthermore, Delta ompR was defective in bacterial motility and flagella synthesis. This defect was due to the low level of expression of flhDC in Delta ompR since overproduction of FlhDC in Delta ompR restored bacterial motility. The importance of two conserved OmpR-binding sites around the flhDC promoter region in the regulation of flhDC expression by OmpR was demonstrated by the fact that mutation of either one or both sites significantly decreased the promoter activity in the wild-type but not in Delta ompR. The binding of OmpR to these two sites was also demonstrated by DNA mobility shift assay. The possible mechanism underlying this positive regulation in Y. pseudotuberculosis is discussed. To our knowledge, this is the first report to demonstrate that OmpR positively regulates flhDC expression.
Hu
Yangbo
Y
Graduate School of the Chinese Academy of Sciences, Beijing 100049, China.|State Key Laboratory of Virology, Wuhan Institute of Virology, the Chinese Academy of Sciences, Wuhan 430071, China.
Wang
Yao
Y
State Key Laboratory of Virology, Wuhan Institute of Virology, the Chinese Academy of Sciences, Wuhan 430071, China.
Ding
Lisha
L
Graduate School of the Chinese Academy of Sciences, Beijing 100049, China.|State Key Laboratory of Virology, Wuhan Institute of Virology, the Chinese Academy of Sciences, Wuhan 430071, China.
Lu
Pei
P
Graduate School of the Chinese Academy of Sciences, Beijing 100049, China.|State Key Laboratory of Virology, Wuhan Institute of Virology, the Chinese Academy of Sciences, Wuhan 430071, China.
Atkinson
Steve
S
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
Chen
Shiyun
S
State Key Laboratory of Virology, Wuhan Institute of Virology, the Chinese Academy of Sciences, Wuhan 430071, China.
D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D005407:Flagella / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D009154:Mutation; D009876:Operon; D011401:Promoter Regions, Genetic; D015534:Trans-Activators / Q000235:genetics / Q000378:metabolism*; D024363:Transcription Initiation Site; D015011:Yersinia pseudotuberculosis / Q000235:genetics* / Q000378:metabolism
D001426:Bacterial Proteins; D015534:Trans-Activators; C112177:osmolarity response regulator proteins