Fig. 4.
MDR1 promoter activity in transformants of the reporter strain CAG48MRR1M4B expressing a wild-type copy of MRR1 (gray arrow), the hyperactive MRR1P683S allele (MRR1*; black arrow), or MRR1 with the indicated internal deletions (amino acids missing from the encoded proteins are indicated to the left). Strains were grown in the absence or presence of benomyl, and the mean fluorescence of the cells was determined by flow cytometry. The results obtained with two independent transformants are shown in each case (means and standard deviations from three experiments). The parental strain CAG48MRR1M4B (mrr1Δ) was included as a control.