FIG. 1.

Construction of deletant and mutant derivatives of a pilEp₁::cat reporter cassette. (A) Nucleotide sequence of the region containing the pilEp₁ promoter (open boxes) fused to the cat gene in the wild-type (WT) reporter cassette. The nucleotides contained within the shaded boxes are protected by IHF (18), with the solid underline indicating the putative 13-bp core consensus sequence previously designated domain 2 (18). The E. coli core consensus sequence (9) is shown above for comparison. Bent arrows indicate the sequences contained within each of the deletant derivatives (Δ −111, Δ −90, Δ −82, Δ −59, and Δ −37). Asterisks indicate the two TSPs (Pla and P1b) associated with pilEp₁ (11). The large ATG defines the start codon of cat. (B) The sequences from −30 to −101 for the WT pilEp₁::cat reporter, the mutated reporter derivatives (IHF mut and UP mut), and each of the deletant reporter constructs (Δ −90, Δ −82, Δ −59, and Δ −37) following subcloning into the unique BglII site within the iga gene fragment in pJKD1854. Nucleotides represented in lowercase letters are vector- or iga-derived. The putative IHF-binding core consensus sequences are underlined. #, a nucleotide substitution generated by site-directed mutagenesis. The −35 regions are boxed.