Iron deprivation of Saccharomyces cerevisiae induces transcription of genes 
required for high-affinity iron uptake. AFT1 mediates this transcriptional 
control. In this report, the 5'-flanking region of FET3, which encodes a 
copper-dependent oxidase required for iron transport, was analyzed and found to 
contain a DNA sequence responsible for AFT1-regulated gene expression. AFT1 was 
capable of interacting specifically with this DNA sequence. A core element 
within this DNA sequence necessary for the binding of AFT1 was also determined. 
In vivo footprinting demonstrated occupancy of the AFT1 binding site in cells 
deprived of iron and not in cells grown in the presence of iron. Thus, the 
environmental signal resulting from iron deprivation was transduced through the 
regulated binding of AFT1 to the FET3 promoter, followed by the activation of 
transcription. A regulon of genes under the control of AFT1 could be defined. 
AFT1 was able to bind to a consensus binding site (PyPuCACCCPu) in the 5' region 
of FRE1, FRE2, FTR1, FTH1 and CCC2.