FIGURE 2.

MDM2 regulates the basal level of ATF3. A and B, p53^−/−/mdm2^+/+and p53^−/−/mdm2^−/− MEF cells were harvested and subjected to immunoblotting (A) or real-time RT-PCR (B). C, LNCaP cells were infected with lentiviruses expressing MDM2-specific shRNA (shM2-1 or shM2-2) for 3 days and then lysed for immunoblotting. D, LNCaP cells expressing shM2-1 or shLuc were lysed for real-time RT-PCR assays. E, p53-deficient (p53^−/−) HCT116 cells were infected with lentiviruses expressing shM2 or shLuc and subjected to immunoblotting as in C.