Figure 2.

Overexpression of cyclin D1 or D1T286A induces apoptosis and G2/M phase delay in MEFs. A: Primary Dmp1^+/+ and Dmp1^−/− MEFs were infected with control retrovirus (V) or retrovirus expressing cyclin D1 (D1) or D1T286A (TA) protein. Cells were starved for 48 hours in serum-free medium and then harvested for immunoblot analysis of cyclin D1, p19^Arf, PARP, cleaved caspase-3, and Dmp1. β-Actin was used as a loading control. B: Primary Dmp1^+/+ and Dmp1^−/− MEFs were infected with control lentivirus or lentivirus expressing HA-tagged cyclin D1 or D1T286A protein. Cells were harvested after 48 hours for immunoblot analysis of HA-cyclin D1, p19^Arf, p16^Ink4a, and Dmp1. β-Actin was used as a loading control. C: Representative images of cell-cycle profiles of Dmp1^+/+ and Dmp1^−/− MEFs infected by lentivirus carrying an empty vector or expressing cyclin D1 or D1T286A (T286A) and stained with propidium iodide 48 hours after infection. D: Quantification of flow cytometric analyses was from three independent experiments. Error bars indicate means ± SD. FL-2A, fluorescent pulse-area; wt, wild-type. ^∗P < 0.05.