FIG. 1.

Organization of the acs promoter region. (A) The sequence of the acs promoter region from positions −290 to +10 relative to the acsP2 transcription start site (+1). The acsP1, acsP2, and pnrfA −10 elements are underlined, and the predicted start points of transcription for acsP1, acsP2, and pnrfA are designated in bold lowercase letters, with the direction of transcription indicated by a horizontal arrow. Inverted arrows specify the location of DNA sites for CRP binding (CRP I and CRP II), while underlining shows the extent of protection afforded by CRP in DNase I footprint experiments. Triangles indicate hypersensitive sites within the relevant strand. The cleavage sites produced by potassium permanganate footprint analysis are in bold and underlined. (B) Schematic of the region, showing the locations of the +1 sites associated with each promoter, each binding site, and the extent of the pacs444 fragment used for DNase I footprint experiments (Fig. 4).