Figure 1.

Glu418Lys is partially resistant to CPT in vivo. (A) Exponentially growing cells in dextrose, transformed with YEpGAL1-wild-type, YEpGAL1-Glu418Lys or YEpGAL1 (vector), serially 10-fold diluted starting from an A₅₉₅ of 0.3; 5 µl, and spotted onto selective media in the presence of dextrose (left) or dextrose plus 0.5 µg/ml CPT (middle), or induced with galactose (right). (B) Number of colonies relative to that obtained at time 0 plotted against time for wild-type, (circle), Glu418Lys mutant (square), Ala653Pro mutant (diamond) and vector (triangle). Exponentially growing cells in dextrose transformed with YCpGAL1-wild-type, YCpGAL1-Glu418Lys, YCpGAL1-Ala653Pro or YCpGAL1 (Vector) were diluited 1:100 into selective medium containing 2% raffinose. After induction with 2% galactose cells were treated with 50 µM CPT or 1% Me₂SO. At various time point aliquots were serially diluted and plated onto selective media containing 2% dextrose. Three different plates were averaged for each data point, and the error bars indicate the standard deviation of the individual values from the mean.