Expression of the Multidrug Resistance Transporter NorA from Staphylococcus aureus Is Modified by a Two-Component Regulatory System
AUTOR(ES)
Fournier, Bénédicte
FONTE
American Society for Microbiology
RESUMO
To dissect genetically the regulation of NorA, a multidrug transporter of Staphylococcus aureus, we analyzed the differential expression of the norA promoter using a transcriptional fusion with a β-lactamase reporter gene. Expression studies with an arlS mutant revealed that the norA promoter is ArlS dependent. The arlR-arlS locus was shown to code for a two-component regulatory system. The protein ArlR has strong similarity to response regulators, and ArlS has strong similarity to protein histidine kinases. We have also analyzed the 350-bp region upstream of the Shine-Dalgarno sequence of norA by gel mobility shift experiments. It was shown that only the 115-bp region upstream of the promoter was necessary for multiple binding of an 18-kDa protein. From transcriptional fusions, we have localized four different putative boxes of 6 bp, which appear to play a role in the binding of the 18-kDa protein and in the up-regulation of norA expression in the presence of the arlS mutation. Furthermore, the gel mobility shift of the 18-kDa protein was modified in the presence of the arlS mutation, and the arlS mutation altered the growth-phase regulation of NorA. These results indicate that expression of norA is modified by a two-component regulatory system.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=94328Documentos Relacionados
- Fluoroquinolone resistance protein NorA of Staphylococcus aureus is a multidrug efflux transporter.
- Inhibition of the multidrug transporter NorA prevents emergence of norfloxacin resistance in Staphylococcus aureus.
- Multiple Novel Inhibitors of the NorA Multidrug Transporter of Staphylococcus aureus
- Evidence for the Existence of a Multidrug Efflux Transporter Distinct from NorA in Staphylococcus aureus
- A Mutation in the 5′ Untranslated Region Increases Stability of norA mRNA, Encoding a Multidrug Resistance Transporter of Staphylococcus aureus