Figure 1

CPT sensitivity in vivo and in vitro . (A) Exponentially growing yeast cells transformed with a single copy plasmid expressing Leu617Ile, Arg621His, Glu710Gly, wild type and vector have been serially 10-fold diluted and spotted onto selective media in the presence of dextrose, of galactose (Gal), or of galactose plus the indicated CPT concentrations. (B) Relaxation of negative supercoiled plasmid in a time course experiment for the wild type and the Glu710Gly mutant in presence of DMSO (lanes 1–9) and 100μM CPT (lanes 10–18); lane 19 represents the control (C) where no protein added. The reaction products are resolved in an agarose gel and visualized with ethidium bromide. The two forms of the supercoiled plasmid DNA are indicated as “Dimer” and “Monomer”.