Figure 6. USP7 is important for arsenic-induced PML degradation.

(A) CNE2 cells were treated with siRNA for USP7 (U) and siRNA for GFP (G) in quadruplicates. 24 hours post-transfection, two samples for each siRNA set were treated with 1 µM As₂O₃ for 6 hours then equal amounts of cell extracts were analyzed by western blotting using the antibodies indicated. (B) CNE2 cells were treated with siRNA and As₂O₃ as in (A). PML was immunoprecipitated from untreated and treated cells and SUMOylated PML was analyzed by western blotting using anti-SUMO1 antibody.