Transcription factor. Essential protein involved in iron uptake responses. Regulates FRO2 at the level of mRNA accumulation and IRT1 at the level of protein accumulation. Confers enhanced iron mobilization responses at low iron supply. Homodimer. Expressed in roots and inflorescence, and to a lower extent, in leaves and stems. In roots, confined to the outer cell layers, specifically in the differentiation zone. Also detected in the endodermis and inner tissues of the central cylinder. In roots by iron deficiency. Repressed by cytokinins. Induced by cold, UV, ethylene (ACC), jasmonic acid (JA), flagellin, and salicylic acid (SA) treatments.