FIGURE 1.

Diagram of selection screen to identify genes involved in the high iron transcriptional response. A Δccc1 yeast strain was generated that contained the promoter region of CCC1 region fused to a lacZ reporter integrated at the HO locus. The strain also contained a deletion in the HIS3 gene and a copy of HIS3 under the control of the GAL1 promoter integrated at the URA3 locus. The strain was transformed with a TRP1 plasmid containing the GAL4 DNA binding domain fused to a YAP5 cysteine-rich activation domain (CRD). In the presence of iron, the cells are HIS3 prototrophs and express β-galactosidase.