Journal Article


James P O'Gara
Stephen G Smith
Vivienne Mahon
Sarah E Rowe



gene deletion growth development reverse transcriptase polymerase chain reaction genetic complementation test biosynthesis staphylococcus epidermidis dna bacterial gene expression regulation bacterial physiology bacterial proteins transcription factors polysaccharides bacterial transcription genetic rnaiii staphylococcus aureus biofilms protein binding rna bacterial promoter regions genetic metabolism polysaccharide intercellular adhesin isolation purification gene expression profiling immunoblotting

A novel role for SarX in Staphylococcus epidermidis biofilm regulation. (2011)

Abstract Biofilm production by staphylococci is an important virulence determinant mediated by the icaADBC-encoded polysaccharide intercellular adhesin (PIA) or by surface and extracellular proteins. Deletion of the Staphylococcus accessory regulator sarX significantly reduced biofilm-forming capacity in Staphylococcus epidermidis CSF41498, whereas multicopy sarX complemented the sarX mutant and increased wild-type biofilm production. In Staphylococcus aureus, SarX negatively regulates the accessory gene regulator (Agr) system, which in turn has strain-specific effects on biofilm regulation. Here we found that purified S. epidermidis SarX protein bound specifically to the agr P3 promoter. However RT-PCR analysis revealed that both mutation of sarX and multicopy sarX activated RNAIII transcription, making it difficult to correlate sarX-mediated biofilm regulation with altered agr activity. In contrast, RT-PCR and immunoblot analysis revealed that icaA transcription and PIA expression were decreased in the sarX mutant, whereas multicopy sarX increased ica and PIA expression. Furthermore, multicopy sarX did not promote biofilms in an icaC mutant. Finally, purified SarX protein bound specifically to the ica operon promoter. Taken together, these data reveal that the S. epidermidis SarX protein regulates the transcriptional activity of the agr and ica loci and controls the biofilm phenotype, primarily by regulating icaADBC transcription and PIA production.
Collections Ireland -> University College Dublin -> PubMed

Full list of authors on original publication

James P O'Gara, Stephen G Smith, Vivienne Mahon, Sarah E Rowe

Experts in our system

James P O'Gara
Royal College of Surgeons in Ireland
Total Publications: 51
Stephen Smith
Trinity College Dublin
Total Publications: 27
Sarah E Rowe
University College Dublin
Total Publications: 4