title: sigmaB activity in a Staphylococcus aureus hemB mutant.
abstract: Inactivation of hemB in Staphylococcus aureus strain Newman resulted in a small-colony phenotype and was accompanied by an altered expression pattern of global regulators and control of virulence factor production. Transcription profiles followed over 15 h by Northern blot analyses revealed that transcripts of the global regulators arl, rot, sae, sarR, sarS, srr, svrA, and sigB disappeared after the exponential phase and that both agr transcripts were completely absent in the hemB mutant. Apart from a general concentration of transcriptional activity to the exponential phase, premature gene expression was observed for rot, hla, and spa. Nevertheless, reported sigmaB-dependent transcripts, such as sarC and clfA, were produced throughout the 15-h growth period monitored. The absence of these transcripts in a hemB sigB double mutant demonstrated their dependence on sigmaB and indicated an unexpected, permanent sigmaB activity in the hemB mutant. Variations in the extents of the directly sigmaB-controlled asp23, rsbVW-sigB, and sarC transcripts argue for additional factors modulating sigmaB activity. This study provides the first extended synopsis of the transcriptional patterns of different regulators over the entire growth cycle in the widely used Newman strain.
authors.affiliation: Department of Medical Microbiology, University of Zürich, Gloriastrasse 32, 8006 Zürich, Switzerland.
authors.forename: Maria M
authors.initials: MM
authors.lastname: Senn
authors.forename: Markus
authors.initials: M
authors.lastname: Bischoff
authors.forename: Christof
authors.initials: C
authors.lastname: von Eiff
authors.forename: Brigitte
authors.initials: B
authors.lastname: Berger-Bächi
mesh_terms: D001426:Bacterial Proteins / Q000032:analysis* / Q000235:genetics; D015152:Blotting, Northern; D017353:Gene Deletion; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D050939:Gene Fusion; D005798:Genes, Bacterial; D005809:Genes, Regulator; D017930:Genes, Reporter; D008156:Luciferases / Q000032:analysis / Q000235:genetics; D016254:Mutagenesis, Insertional; D000623:Porphobilinogen Synthase / Q000235:genetics*; D012329:RNA, Bacterial / Q000032:analysis; D012333:RNA, Messenger / Q000032:analysis; D012808:Sigma Factor / Q000032:analysis* / Q000235:genetics; D013211:Staphylococcus aureus / Q000235:genetics* / Q000254:growth & development; D037521:Virulence Factors / Q000096:biosynthesis
chemical_list: D001426:Bacterial Proteins; D012329:RNA, Bacterial; D012333:RNA, Messenger; C079011:SigB protein, Bacteria; D012808:Sigma Factor; D037521:Virulence Factors; D008156:Luciferases; D000623:Porphobilinogen Synthase