RcdA-binding site on the csgD promoter. (A) DNase-I footprinting assay of RcdA-binding site on the csgD promoter. DNase-I footprinting assay was performed for the spacer between ybjJ and rcdA under the standard reaction conditions as described in Figure 5. Upon increase of RcdA addition, the protected region from DNase-I digestion extended from −192 to −20. In this region, at least four RcdA-box-like sequences exist. (B) The location of transcription factor-binding sites on the csgD promoter. Previously, we determined the binding sites of Cra, CRP, CpxR, CsgD, H-NS, IHF, MlrA, OmpR, and RstA on the csgD promoter (Ogasawara et al. 2010a,b). Concomitant with the increase in RcdA concentration, its binding sequence expanded from the initial binding site so as to overlap the binding sequence by the universal silencer H-NS.