title: Microarray-based analysis of the Staphylococcus aureus sigmaB regulon.
abstract: Microarray-based analysis of the transcriptional profiles of the genetically distinct Staphylococcus aureus strains COL, GP268, and Newman indicate that a total of 251 open reading frames (ORFs) are influenced by sigmaB activity. While sigmaB was found to positively control 198 genes by a factor of > or =2 in at least two of the three genetic lineages analyzed, 53 ORFs were repressed in the presence of sigmaB. Gene products that were found to be influenced by sigmaB are putatively involved in all manner of cellular processes, including cell envelope biosynthesis and turnover, intermediary metabolism, and signaling pathways. Most of the genes and/or operons identified as upregulated by sigmaB were preceded by a nucleotide sequence that resembled the sigmaB consensus promoter sequence of Bacillus subtilis. A conspicuous number of virulence-associated genes were identified as regulated by sigmaB activity, with many adhesins upregulated and prominently represented in this group, while transcription of various exoproteins and toxins were repressed. The data presented here suggest that the sigmaB of S. aureus controls a large regulon and is an important modulator of virulence gene expression that is likely to act conversely to RNAIII, the effector molecule of the agr locus. We propose that this alternative transcription factor may be of importance for the invading pathogen to fine-tune its virulence factor production in response to changing host environments.
authors.affiliation: Department of Medical Microbiology, University of Zurich, CH-8028 Zurich, Switzerland. Bischoff@immv.unizh.ch
authors.forename: Markus
authors.initials: M
authors.lastname: Bischoff
authors.forename: Paul
authors.initials: P
authors.lastname: Dunman
authors.forename: Jan
authors.initials: J
authors.lastname: Kormanec
authors.forename: Daphne
authors.initials: D
authors.lastname: Macapagal
authors.forename: Ellen
authors.initials: E
authors.lastname: Murphy
authors.forename: William
authors.initials: W
authors.lastname: Mounts
authors.forename: Brigitte
authors.initials: B
authors.lastname: Berger-Bächi
authors.forename: Steven
authors.initials: S
authors.lastname: Projan
mesh_terms: D001426:Bacterial Proteins / Q000502:physiology*; D002874:Chromosome Mapping; D015964:Gene Expression Regulation, Bacterial; D020411:Oligonucleotide Array Sequence Analysis; D016366:Open Reading Frames; D018085:Regulon; D012808:Sigma Factor / Q000502:physiology*; D013211:Staphylococcus aureus / Q000235:genetics*; D014774:Virulence
chemical_list: D001426:Bacterial Proteins; C079011:SigB protein, Bacteria; D012808:Sigma Factor