FIG. 6.

Expression of A. nidulans AMT/MEP genes in areA mutant background. (A) Northern analysis of meaA, mepA, and mepB gene expression in the wild-type (MH1) and areAΔ (MH5699) and areA217 (MH341) mutant strains. RNAs were isolated from mycelia grown for 16 h at 37°C in 1% glucose medium, pH 6.5, with 20 mM ammonium (NH₄⁺) and then transferred to nitrogen-free (NF) medium at pH 6.5 for 4 hours. Northern blots were hybridized with probes specific for meaA, mepA, mepB (see Materials and Methods), and A. nidulans histone H3 as a loading control (13), as indicated. (B) Multiplex RT-PCR analysis of meaA, mepA, mepB, and mepC expression in wild-type and areAΔ mutant strains. The name of the respective gene is shown at the top of each picture, and in all cases, the lower band is the internal loading control benA. RT-PCR conditions and primer details are described in Materials and Methods.