FIGURE 5.
Mcm4ΔDDD cells are sensitive to Mcm2 overexpression. Mcm4WT, Mcm4ΔDDD, Mcm2WT, and Mcm2ΔDDD plasmid-supported strains were transformed with either empty pCM190, pCM190-Mcm2WT, or pCM190-Mcm4WT for which expression is under the control of a doxycycline (DOX)-repressible promoter. A, 10-fold serial dilutions of each transformant were spotted on selective media with or without Dox at a starting concentration of 1 × 107 cells/ml and grown for 2 days. B, the same Mcm4WT and Mcm4ΔDDD transformants were grown in selective medium without Dox and the cell concentration determined at the indicated time points. The average of three replicates is shown ± S.D. (error bars). C, serial dilutions were carried as in A, with the addition of strains transformed with pCM190-Mcm2ΔDDD or pCM190-Mcm4ΔDDD, as indicated.