FIGURE 8.

IHF-binding sites in the vvpE regulatory region. A, DNase I protection analysis of IHF binding to the vvpE regulatory region. Lane 1, no IHF added; lanes 2–4, IHF at 200, 400, and 600 nm, respectively. Lanes G, A, T, and C represent the nucleotide sequencing ladders of pKC980. The nucleotides showing an enhanced cleavage in the presence of IHF are indicated by the black boxes, whereas the regions protected by IHF are indicated by the shaded boxes. B, schematic representation of the vvpE regulatory region with the proposed binding sites for SmcR (SB), IHF (IHFB1 and IHFB2), and RNAP, where +1 is the transcription start site of PS. The arrow represents the transcriptional direction and coding region of vvpE, and the solid line represents the upstream region of vvpE, respectively. The sequences for binding of SmcR (SB) and RNAP were determined previously (10, 18). The sequences for the binding of IHF, proposed by the DNase I protection assay, are represented by shaded boxes. The consensus sequences for the binding of IHF from E. coli (37) were shown below the V. vulnificus DNA sequence. W, A or T; R, A or G; N, any base.