congresos y reuniones científicas
A CONSORTIUM OF REGULATORY SYSTEMS CONTROLS THE EXPRESSION OF A Salmonella-SPECIFIC EFFLUX COMPLEX
CERMINATI, SEBASTIÁN; CHECA, SUSANA K.; SONCINI, FERNANDO C.
Congreso; XLVIII Annual Meeting Argentine Society for Biochemistry and Molecular Biology; 2012
CBA efflux systems are tripartite protein complexes that direct export of metal ions, xenobiotics or drugs either from the cytoplasm, the inner membrane or the periplasm into the extracellular space. GesABC is one of the five CBA efflux pumps whose transcription is controlled by the Au-sensor GolS. Among the three transcriptional units controlled by GolS, gesABC has the most divergent GolS-dependent operator, resulting in its delayed expression in the presence of Au ions. Besides its essential role in Au-resistance, the GesABC system can also mediate the transport of different drugs in a strain deleted in the main drug transporter AcrAB, suggesting additional roles for cell detoxification. Using bioinformatics we identified putative cisacting regulatory sequences recognized by global as well as stres sinduced transcriptional regulatory systems that would control the expression of the efflux pump under different conditions. Their effective control of gesABC expression was verified by reporter expression on strains deleted in different regulatory systems. Specific recognition by these systems was confirmed by assays. Our results indicate that a regulatory systems? consortium controls the expression of gesABC, providing the proper supply of the efflux complex according to the quality and severity of different stress conditions that the pathogen encounters.