Fig. 5.
(A) MDR1 promoter activity in transformants of the reporter strain CAG48MRR1M4B expressing a wild-type copy of MRR1 (gray arrow), the hyperactive MRR1P683S allele (black arrow), or fusions of the MRR1 DNA binding domain (codons 1 to 128) to different C-terminal or internal regions of MRR1 (amino acids contained in the encoded proteins are indicated). 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. (B) MDR1 promoter activity in transformants of strain SC5314 expressing the indicated TetR-Mrr1 fusion proteins and containing the Ptet-caGFP reporter fusion. Strains were grown to log phase, 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). Strains expressing a TetR-Gal4AD fusion protein or unfused TetR served as positive and negative controls, respectively.