The E3 Ubiquitin-Ligase Bmi1/Ring1A Controls the Proteasomal Degradation of Top2α Cleavage Complex – A Potentially New Drug Target
Figure 1
VM26 induces proteasomal degradation of Top2α.
HeLa cells were treated for the indicated time with 100 µM VM26 and with control solvent or 20 µM of proteasome inhibitor MG132. At the end of the incubation the medium was replaced with a fresh medium without drugs for 30 minutes to facilitate the recovery of ubiquitin and ubiquitin-like non-conjugated Top2 from the DNA. Top2α and β proteins were recovered from the DNA by alkaline lysis and S7 nuclease treatment and their level was determined by Western-blot with Top2α or β antibodies. The level of γ-Tubulin is shown as control.