title: Regulation of icaR gene expression in Staphylococcus epidermidis.
abstract: LightCycler and conventional reverse transcription-polymerase chain reaction (RT-PCR) were used to examine regulation of icaR, which encodes a repressor of the Staphylococcus epidermidis ica operon. Varying concentrations of NaCl and ethanol activated ica but only high levels of both compounds repressed icaR transcription. Activation of ica by subinhibitory concentrations of tetracycline, which was strain-dependent, was also associated with icaR repression. In an ICAR::Em mutant, NaCl but not ethanol activated ica whereas both compounds repressed icaR expression indicating that environmental regulation of the icaR gene is IcaR-independent. Apparently ethanol signals exclusively through IcaR to activate ica and regulates IcaR at the transcriptional and posttranscriptional levels. NaCl also regulates icaR expression but in addition can activate ica via an icaR-independent pathway.
authors.affiliation: Department of Microbiology, RCSI Education and Research Centre, Smurfit Building, Beaumont Hospital, Royal College of Surgeons in Ireland, 9, Dublin, Ireland.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Conlon
authors.forename: Hilary
authors.initials: H
authors.lastname: Humphreys
authors.forename: James P
authors.initials: JP
authors.lastname: O'Gara
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics*; D018441:Biofilms; D004777:Environment; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects; D016254:Mutagenesis, Insertional / Q000502:physiology; D012097:Repressor Proteins / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D013752:Tetracycline / Q000494:pharmacology; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D001426:Bacterial Proteins; D012097:Repressor Proteins; D013752:Tetracycline