FIG 4.

Effects of HemP on the expression of hmuR and bfd genes. (A and B) qRT-PCR analysis of the ATCC 17616 hmuR (A) and bfd (B) genes, which are both transcriptionally repressed by the Fur-Fe²⁺ complex (12). The cells were cultivated in 1/3LB, washed with M9 minimal medium, and suspended in the same medium. The suspension was exposed to Dpr at 30°C for 30 min and was used to prepare RNA for qRT-PCR analysis. Transcriptional levels are expressed as relative values, compared with the wild-type strain. (C) qRT-PCR analysis of hmuR under conditions of constitutive expression of the hemP gene. A cell suspension, prepared as described above, was exposed to FeCl₃ alone or FeCl₃ and 0.2 mM arabinose and was used for qRT-PCR analysis. Each value with a SD (vertical bar) was obtained in at least three independent experiments. WT, wild type.