FIG. 3.

Promoter activities of the pvdE and pvdF promoter deletion fragments in P. aeruginosa. The positions of the fragments are shown relative to a map of the pvdE-pvdF promoter region, with the nucleotides present in each fragment given relative to the transcript start site of the relevant gene. The transcript start sites (+1) and positions of IS box elements are also shown. The amounts of β-Gal produced from each construct in P. aeruginosa during growth in iron-deficient (−Fe) and iron-replete (+Fe) media, with standard deviations from three independent assays in parentheses, were determined using the method of Miller (15) as described previously (4, 20). Promoter fragments cloned into pMP190 were oriented such that lacZ expression was dependent upon pvdE promoter activity (A and C) or pvdF promoter activity (B and D) as shown. Fragments with the wild-type promoter sequence (A and B) or with mutations in the IS box sequence elements (C and D) were used. Vector control, P. aeruginosa OT11 containing pMP190 vector DNA. OT11pvdS, the pMP190 promoter construct was transformed into OT11pvdS (3) and assays were carried out.