Figure 1

CymR is a direct repressor of transcription from the sigS promoter. (A) A pull down assay was performed using crude protein lysates harvested from RN4220 at hour 2 and a biotinylated sigS promoter DNA probe. The identity of protein bands was determined by LC/MS analysis. (B) qPCR analysis of sigS expression in a cymR mutant compared to its respective parental strain, in the 8325-4 and RN4220 backgrounds. Error bars are shown as ± SEM, * = p <0.05 using a Student’s t-test. (C) An electrophoretic mobility shift assay was performed using purified CymR, and the promoter region of mccAB (positive control), the promoter region of sigS (test), and an intergenic region from the rseP gene (rseP; negative control). CymR was added at increasing concentrations of 0.01, 0.1 and 1 μM in all panels.