NhaR and RcsB independently regulate the osmCp1 promoter of Escherichia coli at overlapping regulatory sites.
Transcription of the Escherichia coli osmC gene is induced by several stress conditions. osmC is expressed from two overlapping promoters, osmCp1 and osmCp2. The proximal promoter, osmCp2, is transcribed at the entry into the stationary phase by the sigma(s) sigma factor. The distal promoter, osmCp1, is activated by NhaR and RcsB. NhaR is a positive regulator of the LysR family and is known to be an activator of the nhaA gene encoding an Na(+)/H(+) antiporter. RcsB is the response regulator of the RcsCDB His-Asp phosphorelay signal transduction system. Genetic data indicated that activation of osmCp1 by both NhaR and RcsB requires the same short sequences upstream of the -35 region of the promoter. Accordingly, DNase I footprint analysis indicated that both activators protect an overlapping region close to the -35 box of the promoter and suggested that the regulatory effect is direct. Despite the overlap of the binding sites, each activator acts independent of the other and is specific for a particular stress. NhaR can stimulate osmCp1 in response to an osmotic signal even in the absence of RcsB. RcsB is responsible for the induction of osmCp1 by alteration of the cell envelope, even in the absence of NhaR. osmCp1 as an example of multiple-stress-responsive promoter is discussed in light of a comparison of the NhaR and RcsB target regions in the Enterobacteriaceae.
Sturny
Rachel
R
Laboratoire de Microbiologie et de Génétique Moléculaire, UMR5100 CNRS-Université Toulouse III, 31062 Toulouse Cedex, France.
Cam
Kaymeuang
K
Gutierrez
Claude
C
Conter
Annie
A
D001426:Bacterial Proteins / Q000378:metabolism*; D001483:Base Sequence; D001665:Binding Sites; D018983:DNA Footprinting; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D004755:Enterobacteriaceae / Q000737:chemistry; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism / Q000502:physiology*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial; D018869:Heat-Shock Response; D008969:Molecular Sequence Data; D011401:Promoter Regions, Genetic / Q000235:genetics*; D016415:Sequence Alignment; D015534:Trans-Activators / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*
D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D029968:Escherichia coli Proteins; C489568:RcsB protein, E coli; D015534:Trans-Activators; D014157:Transcription Factors; C074687:nhaR protein, E coli; C099394:osmC protein, E coli; C074889:RcsB protein, Bacteria; D003851:Deoxyribonucleases