OmpR positively regulates urease expression to enhance acid survival of Yersinia pseudotuberculosis.
Yersinia pseudotuberculosis is an enteric bacterium which must overcome the acidic stress in host organs for successful colonization, but how this bacterium survives in acidic conditions remains largely unknown. In the present study, the importance of OmpR in acid survival of Y. pseudotuberculosis YpIII was confirmed by the fact that mutation of ompR (strain DeltaompR) greatly reduced cell survival at pH 4.5 or lower. To characterize the regulatory role of OmpR in this acid survival process, proteomic analysis was carried out to compare YpIII at pH 7.0 and pH 4.5 with DeltaompR at pH 7.0, and urease components were revealed to be the main targets for OmpR regulation. Addition of urea to the culture medium also enhanced acid survival of YpIII but not DeltaompR and urease activity was significantly induced by acid in YpIII but not in DeltaompR. Each of the seven components of the YpIII urease gene cluster was fused to a lacZ reporter and their expression was dramatically decreased in a DeltaompR background; this supports the notion that OmpR positively regulates urease expression. Furthermore, gel shift analysis revealed that OmpR binds to the deduced promoter regions of three polycistronic transcriptional units (ureABC, ureEF and ureGD) in the urease cluster, suggesting that the regulation of OmpR to urease components is direct. Taken together, these data strongly suggest that OmpR activates urease expression to enhance acid survival in Y. pseudotuberculosis.
Hu
Yangbo
Y
Graduate School of the Chinese Academy of Sciences, Beijing 100049, PR China.|Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, PR China.
Lu
Pei
P
Graduate School of the Chinese Academy of Sciences, Beijing 100049, PR China.|Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, PR China.
Wang
Yao
Y
Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, PR China.
Ding
Lisha
L
Graduate School of the Chinese Academy of Sciences, Beijing 100049, PR China.|Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, PR China.
Atkinson
Steve
S
Institute of Infection, Immunity and Inflammation, Centre for Biomolecular Sciences, University of Nottingham, Nottingham NG7 2UH, UK.
Chen
Shiyun
S
Wuhan Institute of Virology, The Chinese Academy of Sciences, Wuhan 430071, PR China.
D000143:Acids / Q000378:metabolism*; D001426:Bacterial Proteins / Q000378:metabolism*; D004269:DNA, Bacterial / Q000235:genetics; D015180:Electrophoresis, Gel, Two-Dimensional; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial; D006863:Hydrogen-Ion Concentration; D005810:Multigene Family; D011401:Promoter Regions, Genetic; D013312:Stress, Physiological; D015534:Trans-Activators / Q000378:metabolism*; D014158:Transcription, Genetic; D014510:Urease / Q000096:biosynthesis* / Q000235:genetics; D015011:Yersinia pseudotuberculosis / Q000502:physiology*
D000143:Acids; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D015534:Trans-Activators; C112177:osmolarity response regulator proteins; D014510:Urease