Figure 2. Studying C. trachomatis ompA promoter activity in E. coli.

(a) Promoter-lacZ constructions. The organization of the regulatory region upstream of the ompA coding region (top) and DNA fragments used to create the lacZ reporter strains are shown. Positions relative to the translation start codon ATG of ompA are indicated. (b) Results of β-gal activity. E. coli strains, FW/P21, FW/P2, and FW/P1, were harvested at the exponential phase and subjected to β-gal assays. Strain FW (vector only) was used as a control. Data are presented as mean ± SD from a representative experiment of three independent experiments. (c) Base sequences of putative ompA promoters used in this work. Putative −35/−10 hexamers are bolded. The E. coli σ⁷⁰ or C. trachomatis σ⁶⁶ consensus recognition sequences are listed at the top.