GATA-type transcription repressor that regulates iron- acquisition genes through specific binding the GATA sequence element 5'-(G/A)ATC(T/A)GATAA-3' of target promoters in an iron- and zinc-dependent manner (PubMed:18549241, PubMed:22117028). Regulation occurs via direct binding of iron ions (PubMed:18549241). Iron acquisition regulation is critical for survival under both iron-limiting conditions (to acquire essential iron) and iron-replete conditions (to limit iron toxicity) (PubMed:22117028). SRE1 targets include genes encoding a number of key iron-regulated factors such as those involved in siderophore biosynthesis, presumed ferric reductase activity, iron-responsive transcriptional regulation, oxidative stress response, as well as genes encoding a number of putative oxidoreductases, metabolic and mitochondrial enzymes, superoxide dismutase, and genes previously identified as induced during nitrosative stress (PubMed:22117028). Constitutively expressed in high-iron medium, whereas expression is reduced approximately 2.5-fold when an iron chelator, such as deferoxamine, is added to the growth medium (PubMed:18549241). The conserved cystein-rich region (CRR) localized between the zinc fingers is also involved in DNA-binding and transcription repressor activity (By similarity). Impairs the repression of siderophore biosynthesis and utilization genes in the presence of abundant iron and thus produces siderophores even under iron-replete conditions (PubMed:22117028).