Sigma(s)-Dependent carbon-starvation induction of pbpG (PBP 7) is required for the starvation-stress response in Salmonella enterica serovar Typhimurium.
Carbon-energy source starvation is a commonly encountered stress that can influence the epidemiology and virulence of Salmonella enterica serovars. Salmonella responds to C-starvation by eliciting the starvation-stress response (SSR), which allows for long-term C-starvation survival and cross-resistance to other stresses. The stiC locus was identified as a C-starvation-inducible, sigma(S)-dependent locus required for a maximal SSR. We report here that the stiC locus is an operon composed of the yohC (putative transport protein) and pbpG (penicillin-binding protein-7/8) genes. yohC pbpG transcription is initiated from a sigma(S)-dependent C-starvation-inducible promoter upstream of yohC. Another (sigma(S)-independent) promoter, upstream of pbpG, drives lower constitutive pbpG transcription, primarily during exponential phase. C-starvation-inducible pbpG expression was required for development of the SSR in 5 h, but not 24 h, C-starved cells; yohC was dispensable for the SSR. Furthermore, the yohC pbpG operon is induced within MDCK epithelial cells, but was not essential for oral virulence in BALB/c mice. Thus, PBP 7 is required for physiological changes, occurring within the first few hours of C-starvation, essential for the development of the SSR. Lack of PBP 7, however, can be compensated for by further physiological changes developed in 24 h C-starved cells. This supports the dynamic overlapping and distinct nature of resistance pathways within the Salmonella SSR.
Kenyon
William J
WJ
Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA.
Nicholson
Kristy L
KL
Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA.
Rezuchova
Bronislava
B
Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic.
Homerova
Dagmar
D
Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic.
Garcia-Del Portillo
Francisco
F
The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall, Vancouver, BC, Canada V6T 1Z4.|Departamento de Biotecnología Microbiana, Centro Nacional de Biotecnología-CSIC, C/ Darwin 3, 28049 Madrid, Spain.
Finlay
B Brett
BB
The University of British Columbia, Michael Smith Laboratories, 301-2185 East Mall, Vancouver, BC, Canada V6T 1Z4.
Pallen
Mark J
MJ
Division of Immunity and Infection, Medical School, University of Birmingham, Birmingham B15 2TT, UK.
Kormanec
Jan
J
Institute of Molecular Biology, Slovak Academy of Sciences, Dubravska cesta 21, 845 51 Bratislava 45, Slovak Republic.
Spector
Michael P
MP
Department of Biomedical Sciences, University of South Alabama, Mobile, AL 36688, USA.
D000222:Adaptation, Physiological; D001426:Bacterial Proteins / Q000378:metabolism*; D002244:Carbon / Q000378:metabolism*; D002453:Cell Cycle; D002460:Cell Line; D015964:Gene Expression Regulation, Bacterial; D018384:Oxidative Stress; D046915:Penicillin-Binding Proteins / Q000096:biosynthesis*; D033903:Periplasmic Proteins / Q000096:biosynthesis*; D012486:Salmonella typhimurium / Q000235:genetics / Q000254:growth & development* / Q000502:physiology*; D012808:Sigma Factor / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism
D001426:Bacterial Proteins; C436969:PbpG protein, Bacillus subtilis; D046915:Penicillin-Binding Proteins; D033903:Periplasmic Proteins; D012808:Sigma Factor; D014157:Transcription Factors; C069567:sigma factor KatF protein, Bacteria; D002244:Carbon