FIGURE 2.

Identification of a mutant SSQ1 that affects Yap5 induction of CCC1. A, serial dilutions of the parental strain and UV mutant (UV mut) 109b cells were spotted on plates in the presence or absence of histidine. Cells were grown for 3 days, and then a β-galactosidase assay was performed. B, parental, UV mutant 109b, and UV mutant 109b, transformed with library plasmid 16 (lib #16), were grown overnight in low iron medium, 500 μm iron was added for 2.5 h, and a quantitative β-galactosidase assay performed. Cell protein was determined, and the data are expressed as specific activity. The data are the average of at least three experiments and are presented as the mean ± S.D. Bottom panel: cells from above were spotted in a serial dilution in the presence or absence or histidine and grown for 3 days. C, a β-galactosidase assay and a plate spot assay were performed for mutant cells transformed with a control vector or a subcloned SSQ1 plasmid. Cell protein was determined, and the β-galactosidase assay data are expressed as specific activity. The data are the average of at least three experiments and are presented as the mean ± S.D.