Figure 3. fio1⁺ transcription is constantly repressed in a Fep1-dependent manner in php4Δ fra2Δ cells.

A, RNase protection analysis of the fio1⁺ and act1⁺ transcript levels in wild-type (WT), php4Δ fep1Δ, php4Δ fra2Δ, and php4Δ fep1Δ fra2Δ strains exposed to 250 µM Dip or 100 µM FeCl₃ or left untreated (-). When indicated, php4Δ fep1Δ and php4Δ fep1Δ fra2Δ cells were transformed with an integrative plasmid that encoded a functional TAP-tagged fep1⁺ allele. B, Total RNA from cultures incubated under conditions described in panel A were used to probe steady-state levels of fep1⁺ and act1⁺ mRNAs. NS, non-specific signal. The results are representative of three independent experiments.