Figure 4.

Hfq is necessary for the binding of CzcR to the oprD promoter. (A) Chromosome immunoprecipitation experiment performed on the WT strain and the hfq mutant using anti-CzcR antibody. The experiment was performed on cultures grown in the absence or presence of 0.5 mM ZnCl₂, as indicated. Results represent the average of 3 independent experiments and standard deviations are indicated. Statistical analysis with the Student test gave a p value below 0.0001 (****); (B) Amount of oprD mRNA analyzed by quantitative RT-PCR in the WT and the hfq⁻ mutants cultivated in the absence or presence of 0.5 mM ZnCl₂ as indicated. The amount of mRNA is represented relative to the WT strain cultivated in the absence of metal. ChIP (chromosome immunoprecipitation) was performed in triplicate on three independent experiments. Error bars represent the standard deviations of three independent determinations.