Open AccessThe Response Regulator CroR Modulates Expression of the Secreted Stress-Induced SalB Protein in Enterococcus faecalis
Author(s) -
Cécile Muller,
Yoann Le Breton,
Thierry Morin,
Abdellah Benachour,
Yanick Auffray,
Alain Rincé
Publication year - 2006
Publication title -
journal of bacteriology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.652
H-Index - 246
eISSN - 1067-8832
pISSN - 0021-9193
DOI - 10.1128/jb.188.7.2636-2645.2006
Subject(s) - biology , enterococcus faecalis , regulator , bacterial protein , microbiology and biotechnology , protein expression , response regulator , enterococcus , fight or flight response , bacteria , genetics , gene , antibiotics , staphylococcus aureus
TheEnterococcus faecalis two-component signal transduction system CroRS, also referred as the RR-HK05 pair, is required for intrinsic β-lactam resistance (Y. R. Comenge, R. Quintiliani, Jr., L. Li, L. Dubost, J. P. Brouard, J. E. Hugonnet, and M. Arthur, J. Bacteriol. 185:7184-7192, 2003) and is also suspected to be involved in the expression ofsalB (previously referred to assagA ), a gene important for resistance to environmental stress and cell morphology (Y. Le Breton, G. Boël, A. Benachour, H. Prévost, Y. Auffray, and A. Rincé, Environ. Microbiol. 5:329-337, 2003). In this report, we provide genetic and biochemical evidence thatsalB encodes a secreted protein that is expressed from a monocistronic stress-inducible operon. Consistent with CroR being a direct transcriptional activator of thesalB expression, CroR was found to bind to thesalB promoter region in electrophoretic mobility shift assays. Interestingly, we provide evidence that SalB does not play a role in the intrinsic β-lactam resistance associated with CroRS. We also show that the CroRS system is able to regulate its own expression. The sequence of the CroRS binding site in thesalB andcroR promoter regions was determined using DNase I footprinting assays.