Scientific article

Control of the Staphylococcus aureus toxic shock tst promoter by the global regulator SarA

Published inJournal of bacteriology, vol. 192, no. 22, p. 6077-6085
Publication date2010

The Staphylococcus aureus SarA global regulator controls the expression of numerous virulence genes, often in conjunction with the agr quorum-sensing system and its effector RNA, RNAIII. In the present study, we have examined the role of both SarA and RNAIII on the regulation of the promoter of tst, encoding staphylococcal superantigen toxic shock syndrome toxin 1 (TSST-1). In vitro DNA-protein interaction studies with purified SarA using gel shift and DNase I protection assays revealed one strong SarA binding site and evidence for a weaker site nearby within the minimal 400-bp promoter region upstream of tst. In vivo analysis of tst promoter activation using a p(tst)-luxAB reporter inserted in the chromosome revealed partial but not complete loss of tst expression in a Deltahld-RNAIII strain. In contrast, disruption of sarA abrogated tst expression. No significant tst expression was found for the double Deltahld-RNAIII-DeltasarA mutant. Introduction of a plasmid containing cloned hld-RNAIII driven by a non-agr-dependent promoter, p(HU), into isogenic parental wild-type or DeltasarA strains showed comparable levels of RNAIII detected by quantitative reverse transcription-PCR (qRT-PCR) but a two-log(10) reduction in p(tst)-luxAB reporter expression in the DeltasarA strain, arguing that RNAIII levels alone are not strictly determinant for tst expression. Collectively, our results indicate that SarA binds directly to the tst promoter and that SarA plays a significant and direct role in the expression of tst.

  • Artificial Gene Fusion
  • Bacterial Proteins/genetics/*metabolism
  • Bacterial Toxins/*biosynthesis
  • Base Sequence
  • DNA, Bacterial/metabolism
  • Enterotoxins/*biosynthesis
  • Gene Deletion
  • *Gene Expression Regulation, Bacterial
  • Genes, Reporter
  • Luciferases/genetics/metabolism
  • Molecular Sequence Data
  • Plasmids
  • Promoter Regions, Genetic
  • Protein Binding
  • RNA, Bacterial/genetics/*metabolism
  • Sequence Deletion
  • Shock, Septic
  • Staphylococcus aureus/*physiology
  • Superantigens/*biosynthesis
Citation (ISO format)
ANDREY, Diego Olivier et al. Control of the Staphylococcus aureus toxic shock tst promoter by the global regulator SarA. In: Journal of bacteriology, 2010, vol. 192, n° 22, p. 6077–6085. doi: 10.1128/JB.00146-10
Main files (1)
ISSN of the journal0021-9193

Technical informations

Creation05/23/2012 8:44:01 AM
First validation05/23/2012 8:44:01 AM
Update time03/14/2023 5:31:27 PM
Status update03/14/2023 5:31:27 PM
Last indexation02/12/2024 8:08:00 PM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack