Figure 1. p21 degradation is mediated by the CRL4^Cdt2 ligase complex.

A) Schematic illustrating the experimental protocol for siRNA knockdown of ligase components in Figures 1B and 1C. B and C) p21 degradation requires DDB1 (B) and Cdt2 (C). Murine A9 cells were targeted with control siRNA or siRNA to DDB1 (B) or Cdt2 (C) as depicted in Figure 1A. Uninfected control cells were harvested at the time of release (Mock T0). Infections were done at the time of release at an MOI of 10 before harvest at 24 and 40 hr pi. Western blots were performed using antibodies against the indicated proteins.