FIG 7.
Assessing expression of iutE in a ΔripA mutant. (A) The relative transcript levels for ripA were determined by comparing the C. diphtheriae 1737 wild-type (wt) and ΔdtxR mutant strains following growth in mPGT with iron supplementation as indicated. (B) The relative transcript levels for iutE, iutA, and the putative RipA-regulated acn gene were measured following growth in modified mPGT with Fe supplementation as indicated. Relative expression was determined using the ΔΔCq method; statistical significance was determined by two-way ANOVA and multiple-comparison test on ΔCq values. **, P ≤ 0.0001 (n = 3). (C) EMSA performed with recombinant RipA and the promoter regions pacn, piutE-FL, and piutE.