Regulation of Expression of Oxacillin-Inducible Methionine Sulfoxide Reductases inStaphylococcus aureus

[摘要] Cell wall-active antibiotics cause induction of a locus that leads to elevated synthesis of two methionine sulfoxide reductases (MsrA1 and MsrB) inStaphylococcus aureus. To understand the regulation of this locus, reporter strains were constructed by integrating a DNA fragment consisting of themsrA1/msrBpromoter in front of a promoterlesslacZgene in the chromosome of wild-type and MsrA1-, MsrB-, MsrA1/MsrB-, and SigB-deficient methicillin-sensitiveS. aureusstrain SH1000 and methicillin-resistantS. aureusstrain COL. These reporter strains were cultured in TSB and the cellular levels ofβ-galactosidase activity in these cultures were assayed during different growth phases.β-galactosidase activity assays demonstrated that the lack of MsrA1, MsrB, and SigB upregulated themsrA1/msrBpromoter inS. aureusstrain SH1000. InS. aureusstrain COL, the highest level ofβ-galactosidase activity was observed under the conditions when both MsrA1 and MsrB proteins were absent. The data suggest that themsrA1/msrBlocus, in part, is negatively regulated by MsrA1, MsrB, and SigB inS. aureus.

[学科分类] 微生物学和免疫学