Fig. 9.

Apoptin induces the degradation of MDC1 in a proteasome-dependent manner. (A) H1299 cells were infected with Ad-Apwt or Ad-LacZ and harvested at the indicated time points. Equal quantities of nuclear extract were loaded in each lane and separated by SDS-PAGE. The levels of MDC1 protein were then monitored by immunoblotting. Apoptin expression was detected using anti-FLAG, and actin was included as a loading control. (B) H1299 cells were infected with Ad-Apwt or Ad-LacZ for 40 h. Cells were then treated with cycloheximide for the indicated amounts of time, and nuclear extracts were prepared. Equal quantities of protein were separated by SDS-PAGE, and the levels of MDC1 protein were then monitored by immunoblotting. Apoptin expression was detected using anti-FLAG, and actin was included as a loading control. (C) H1299 cells were infected with Ad-Apwt or Ad LacZ for 42 h. Cells were then treated with MG132 at the indicated concentrations for 6 h, and nuclear extracts were prepared. Equal quantities of protein were separated by SDS-PAGE, and the levels of MDC1 protein were then monitored by immunoblotting. Apoptin expression was detected using anti-FLAG, and actin was included as a loading control.