Analysis of drug resistance properties dependent on TAC1 alleles. (A) Drug susceptibility testing of C. albicans tac1Δ/Δ mutant and TAC1 revertant strains with different TAC1 alleles. Drug susceptibility assays were carried out by plating serial dilutions of overnight cultures onto YEPD agar plates containing different drugs as indicated. Plates were incubated for 48 hr at 35°. MIC assays were performed as described in materials and methods. (B) Immunodetection of Cdr1p and Cdr2p in tac1Δ/Δ mutant and TAC1 revertant strains with different TAC1 alleles. Protein extracts of each strain were separated on SDS-10% polyacrylamide gels and immunoblotted with rabbit polyclonal anti-Cdr1p and anti-Cdr2p as described previously (de Micheli et al. 2002). C. albicans strains were grown in liquid YEPD to midlog phase and exposed (+) or not (−) to fluphenazine (10 μg/ml) for 20 min. The following Ura+ strains correspond to the following genotypes: CAF2-1, TAC1-1/TAC1-2; DSY2903, tac1-1Δ/tac1-2Δ; DSY2925-47, tac1Δ/Δ + TAC1-3; DSY2925-18, tac1Δ/Δ + TAC1-4; DSY2984, tac1Δ/Δ + TAC1-5; DSY3010-80, tac1Δ/Δ + TAC1-6; DSY3010-113, tac1Δ/Δ + TAC1-7-FH1; DSY3013, tac1Δ/Δ + TAC1-7-FH3. For phenotypes and genotypes of the different strains of this study refer to supplemental Table S1 at http://www.genetics.org/supplemental/.