title: GdpS contributes to Staphylococcus aureus biofilm formation by regulation of eDNA release.
abstract: In Staphylococcus aureus, the role of the GGDEF domain-containing protein GdpS remains poorly understood. Previous studies reported that gdpS mutant strains had decreased biofilm formation due to changes in icaADBC expression that were independent of cyclic-di-GMP levels. We deleted gdpS in three unrelated S. aureus isolates, and analyzed the resultant mutants for alterations in biofilm formation, metabolism and transcription. Dynamic imaging during biofilm development showed that GdpS inhibited early biofilm formation in only two out of the three strains examined, without affecting bacterial survival. However, quantification of biofilm formation using crystal violet staining revealed that inactivation of gdpS affected biofilm formation in all three studied strains. Extraction of metabolites from S. aureus cells confirmed the absence of cyclic-di-GMP, suggesting that biofilm formation in this species differs from that in other Gram-positive organisms. In addition, targeted mutagenesis demonstrated that the GGDEF domain was not required for GdpS activity. Transcriptomic analysis revealed that the vast majority of GGDEF-regulated genes were involved in virulence, metabolism, cell wall biogenesis and eDNA release. Finally, expression of lrgAB or deletion of cidABC in a strain lacking gdpS confirmed the role of GdpS on regulation of eDNA production that occurred without an increase in cell autolysis, but with a late increase in holin-mediated autolysis, in the presence of high oxacillin concentrations. In summary, S. aureus GdpS contributes to cell-to-cell interactions during early biofilm formation by influencing expression of lrgAB and cidABC mediated eDNA release. We conclude that GdpS acts as a negative regulator of eDNA release.
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland. Electronic address: adrien.fischer@genomic.ch.
authors.forename: A
authors.initials: A
authors.lastname: Fischer
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: K
authors.initials: K
authors.lastname: Kambara
authors.affiliation: Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Strasse 4, 17487 Greifswald, Germany.
authors.forename: H
authors.initials: H
authors.lastname: Meyer
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: L
authors.initials: L
authors.lastname: Stenz
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: E-J
authors.initials: EJ
authors.lastname: Bonetti
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Girard
authors.affiliation: Institute of Biochemistry, University of Greifswald, Felix-Hausdorff-Strasse 4, 17487 Greifswald, Germany.
authors.forename: M
authors.initials: M
authors.lastname: Lalk
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: P
authors.initials: P
authors.lastname: Francois
authors.affiliation: Genomic Research Laboratory, Department of Medical Specialties, Geneva University Hospitals, 1211 Geneva 14, Switzerland.
authors.forename: J
authors.initials: J
authors.lastname: Schrenzel
mesh_terms: D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D018441:Biofilms / Q000254:growth & development*; D004269:DNA, Bacterial / Q000378:metabolism*; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D006801:Humans; D061848:Optical Imaging; D013211:Staphylococcus aureus / Q000235:genetics / Q000502:physiology*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D004269:DNA, Bacterial; D014157:Transcription Factors
keywords: Biofilm; Cyclic-di-GMP; GGDEF domain; Staphylococcus aureus; Transcriptomic; cidABC; eDNA; lrgAB