The E3 Ubiquitin-Ligase Bmi1/Ring1A Controls the Proteasomal Degradation of Top2α Cleavage Complex – A Potentially New Drug Target
Figure 5
Ring1A but not Ring1B is required for VM26 induced degradation of Top2α HeLa cells transfected with siRNA targeting Bmi1, Ring1A, Ring1B or control siRNA (SC) were treated 48 hours later with 100 µM VM26 for the indicated time.
Top2α protein was recovered from the DNA by alkaline lysis and S7 nuclease treatment and its level was determined by Western-blot with Top2α antibody. Levels of Top1 are shown as control. The activity of Ring1A and Ring1B targeting siRNAs was verified by Western-blot analysis with the appropriate antibodies (lower panels).