FIG. 2.

Identification of the Mdm2-inducible elements in the cell cycle-responsive promoters. tsBN462 cells were transfected in six-well dishes with luciferase reporters containing either wild-type or point-mutated promoters from the B-myb, cyclin A, and cdc25C genes (1 μg) and increasing amounts of the Mdm2 expression vector (pCMV-Mdm2; 0.1, 0.2, 0.5, and 1 μg). After transfection the cells were transferred to 39°C, and 24 h later the luciferase activities were measured. Luciferase activities were corrected for variations in transfection efficiency by using the internal control (pSG5-LacZ; 1 μg/ml). They are presented relative to the control (set to 1) that was transfected in duplicate in each experiment. The fold activations are the averages from three independent experiments, and the error bars indicate the standard deviations.