AraC-type regulator Rbf controls the Staphylococcus epidermidis biofilm phenotype by negatively regulating the icaADBC repressor SarR

Sarah E. Rowe, Christopher Campbell, Colm Lowry, Sinead T. O'Donnell, Michael E. Olson, Jill K. Lindgren, Elaine M. Waters, Paul D Fey, James P. O'Gara

Research output: Contribution to journalArticle

6 Citations (Scopus)

Abstract

Regulation of icaADBC-encoded polysaccharide intercellular adhesin (PIA)/poly-N-acetylglucosasmine (PNAG) production in staphylococci plays an important role in biofilm-associated medical-device-related infections. Here, we report that the AraCtype transcriptional regulator Rbf activates icaADBC operon transcription and PIA production in Staphylococcus epidermidis. Purified recombinant Rbf did not bind to the ica operon promoter region in electrophoretic mobility shift assays (EMSAs), indicating that Rbf regulates ica transcription indirectly. To identify the putative transcription factor(s) involved in Rbf-mediated icaADBC regulation, the ability of recombinant Rbf to interact with the promoter sequences of known icaADBC regulators was investigated. Recombinant Rbf bound to the sarR promoter and not the sarX, sarA, sarZ, spx, and srrA promoters. Reverse transcription (RT)-PCR demonstrated that Rbf acts as a repressor of sarR transcription. PIA expression and biofilm production were restored to wild-type levels in an rbf sarR double mutant grown in brain heart infusion (BHI) medium supplemented with NaCl, which is known to activate the ica locus, but not in BHI medium alone. RT-PCR further demonstrated that although Rbf does not bind the sarX promoter, it nevertheless exerted a negative effect on sarX expression. Apparently, direct downregulation of the SarR repressor by Rbf has a dominant effect over indirect repression of the SarX activator by Rbf in the control of S. epidermidis PIA production and biofilm formation.

Original languageEnglish (US)
Pages (from-to)2914-2924
Number of pages11
JournalJournal of bacteriology
Volume198
Issue number21
DOIs
StatePublished - Jan 1 2016

Fingerprint

Staphylococcus epidermidis
Biofilms
Phenotype
Operon
Reverse Transcription
Polymerase Chain Reaction
Brain
Electrophoretic Mobility Shift Assay
Staphylococcus
Genetic Promoter Regions
Transcription Factors
Down-Regulation
Equipment and Supplies
polysaccharide intercellular adhesin
Infection

ASJC Scopus subject areas

  • Microbiology
  • Molecular Biology

Cite this

Rowe, S. E., Campbell, C., Lowry, C., O'Donnell, S. T., Olson, M. E., Lindgren, J. K., ... O'Gara, J. P. (2016). AraC-type regulator Rbf controls the Staphylococcus epidermidis biofilm phenotype by negatively regulating the icaADBC repressor SarR. Journal of bacteriology, 198(21), 2914-2924. https://doi.org/10.1128/JB.00374-16

AraC-type regulator Rbf controls the Staphylococcus epidermidis biofilm phenotype by negatively regulating the icaADBC repressor SarR. / Rowe, Sarah E.; Campbell, Christopher; Lowry, Colm; O'Donnell, Sinead T.; Olson, Michael E.; Lindgren, Jill K.; Waters, Elaine M.; Fey, Paul D; O'Gara, James P.

In: Journal of bacteriology, Vol. 198, No. 21, 01.01.2016, p. 2914-2924.

Research output: Contribution to journalArticle

Rowe, SE, Campbell, C, Lowry, C, O'Donnell, ST, Olson, ME, Lindgren, JK, Waters, EM, Fey, PD & O'Gara, JP 2016, 'AraC-type regulator Rbf controls the Staphylococcus epidermidis biofilm phenotype by negatively regulating the icaADBC repressor SarR', Journal of bacteriology, vol. 198, no. 21, pp. 2914-2924. https://doi.org/10.1128/JB.00374-16
Rowe, Sarah E. ; Campbell, Christopher ; Lowry, Colm ; O'Donnell, Sinead T. ; Olson, Michael E. ; Lindgren, Jill K. ; Waters, Elaine M. ; Fey, Paul D ; O'Gara, James P. / AraC-type regulator Rbf controls the Staphylococcus epidermidis biofilm phenotype by negatively regulating the icaADBC repressor SarR. In: Journal of bacteriology. 2016 ; Vol. 198, No. 21. pp. 2914-2924.
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abstract = "Regulation of icaADBC-encoded polysaccharide intercellular adhesin (PIA)/poly-N-acetylglucosasmine (PNAG) production in staphylococci plays an important role in biofilm-associated medical-device-related infections. Here, we report that the AraCtype transcriptional regulator Rbf activates icaADBC operon transcription and PIA production in Staphylococcus epidermidis. Purified recombinant Rbf did not bind to the ica operon promoter region in electrophoretic mobility shift assays (EMSAs), indicating that Rbf regulates ica transcription indirectly. To identify the putative transcription factor(s) involved in Rbf-mediated icaADBC regulation, the ability of recombinant Rbf to interact with the promoter sequences of known icaADBC regulators was investigated. Recombinant Rbf bound to the sarR promoter and not the sarX, sarA, sarZ, spx, and srrA promoters. Reverse transcription (RT)-PCR demonstrated that Rbf acts as a repressor of sarR transcription. PIA expression and biofilm production were restored to wild-type levels in an rbf sarR double mutant grown in brain heart infusion (BHI) medium supplemented with NaCl, which is known to activate the ica locus, but not in BHI medium alone. RT-PCR further demonstrated that although Rbf does not bind the sarX promoter, it nevertheless exerted a negative effect on sarX expression. Apparently, direct downregulation of the SarR repressor by Rbf has a dominant effect over indirect repression of the SarX activator by Rbf in the control of S. epidermidis PIA production and biofilm formation.",
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AU - Olson, Michael E.

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