SoxS regulates the expression of the Salmonella enterica serovar Typhimurium ompW gene.
OmpW of Salmonella enterica serovar Typhimurium has been described as a minor porin involved in osmoregulation, and is also affected by environmental conditions. Biochemical and genetic evidence from our laboratory indicates that OmpW is involved in efflux of and resistance towards paraquat (PQ), and its expression has been shown to be activated in response to oxidative stress. In this study we have explored ompW expression in response to PQ. Primer extension and transcriptional fusions showed that its expression was induced in the presence of PQ. In silico analyses suggested a putative binding site for the SoxS transcriptional factor at the ompW regulatory region. Electrophoretic mobility shift assays (EMSAs) and footprinting experiments showed that SoxS binds at a region that starts close to -54 and ends at about -197 upstream of the transcription start site. Transcriptional fusions support the relevance of this region in ompW activation. The SoxS site is in the forward orientation and its location suggests that the ompW gene has a class I SoxS-dependent promoter.
Gil
F
F
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Hernández-Lucas
I
I
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.
Polanco
R
R
Laboratorio de Bioquímica, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Pacheco
N
N
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Collao
B
B
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Villarreal
J M
JM
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Nardocci
G
G
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
Calva
E
E
Departamento de Microbiología Molecular, Instituto de Biotecnología, Universidad Nacional Autónoma de México, Cuernavaca, Mexico.
Saavedra
C P
CP
Laboratorio de Microbiología Molecular, Departamento de Ciencias Biológicas, Universidad Andrés Bello, Santiago, Chile.
D001425:Bacterial Outer Membrane Proteins / Q000096:biosynthesis / Q000235:genetics; D001426:Bacterial Proteins / Q000378:metabolism*; D004269:DNA, Bacterial / Q000032:analysis / Q000235:genetics; D004591:Electrophoresis, Polyacrylamide Gel; D024202:Electrophoretic Mobility Shift Assay; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects*; D006540:Herbicides / Q000494:pharmacology; D010269:Paraquat / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D012486:Salmonella typhimurium / Q000187:drug effects / Q000235:genetics / Q000378:metabolism*; D017422:Sequence Analysis, DNA; D015534:Trans-Activators / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects
D001425:Bacterial Outer Membrane Proteins; D001426:Bacterial Proteins; D004269:DNA, Bacterial; D006540:Herbicides; C485381:SoxS protein, Salmonella enterica; D015534:Trans-Activators; D010269:Paraquat