FIG. 6.

Graphical representations showing the fold increase in drug resistance of WT and erg mutant strains of S. cerevisiae upon transformation with Cdr1p- and CaMdr1p-encoding plasmids (see Materials and Methods). The fold increase in resistance to each drug was calculated as the difference in resistance between the nontransformant and transformant pair for each cell type. MTX is the substrate for CaMdr1p (24), and the fold change in resistance is much higher for CaMDR1-transformed erg mutant cells than for CDR1-transformed erg mutant cells. Note the change in the x axis for fold MTX resistance.