srbA expression is transcriptionally upregulated by iron starvation and SrbA-deficiency downregulates the SreA regulon independent of SreA and HapX, as well as the ergosterol biosynthetic erg3 and erg25 and the heme-biosynthetic hem13.

For Northern analysis, total RNA was isolated from A. fumigatus strains grown for 24 h in liquid cultures at 37°C at 200 rpm during iron-replete (+Fe) and depleted (−Fe) conditions. Ethidium bromide-stained rRNA is shown as control for loading and quality of RNA.