Journal of Bacteriology
Geisel School of Medicine
The Vibrio cholerae BreR protein is a transcriptional repressor of the breAB efflux system operon, which encodes proteins involved in bile resistance. In a previous study (F. A. Cerda-Maira, C. S. Ringelberg, and R. K. Taylor, J. Bacteriol. 190:7441-7452, 2008), we used gel mobility shift assays to determine that BreR binds at two independent binding sites at the breAB promoter and a single site at its own promoter. Here it is shown, by DNase I footprinting and site-directed mutagenesis, that BreR is able to bind at a distal and a proximal site in the breAB promoter. However, only one of these sites, the proximal 29-bp site, is necessary for BreR-mediated transcriptional repression of breAB expression. In addition, it was determined that BreR represses its own expression by recognizing a 28-bp site at the breR promoter. These sites comprise regions of dyad symmetry within which residues critical for BreR function could be identified. The BreR consensus sequence AANGTANAC-N(6)-GTNTACNTT overlaps the -35 region at both promoters, implying that the repression of gene expression is achieved by interfering with RNA polymerase binding at these promoters.
Cerda-Maira FA, Kovacikova G, Jude BA, Skorupski K, Taylor RK. Characterization of BreR interaction with the bile response promoters breAB and breR in Vibrio cholerae. J Bacteriol. 2013 Jan;195(2):307-17. doi: 10.1128/JB.02008-12. Epub 2012 Nov 9. PMID: 23144245; PMCID: PMC3553838.
Dartmouth Digital Commons Citation
Cerda-Maira, Francisca A.; Kovacikova, Gabriela; Jude, Brooke A.; Skorupski, Karen; and Taylor, Ronald, "Characterization of BreR Interaction with the Bile Response Promoters breAB and breR in Vibrio cholerae" (2013). Dartmouth Scholarship. 1048.