(A) Endogenous SOX9 protein turnover in the presence of cycloheximide following RNAi depletion of FBW7α, β or γ. HEK293 cells were transfected with 20 nM of non-targeting scramble RNA or those specifically targeting FBW7α, β or γ for 72 hours prior to chase with addition of 100 ng /mL cycloheximide. Immunoblot of Cyclin E, an established SCF-FBW7 substrate, was used to assess the efficacy of RNAi-mediated depletion of FBW7 protein with GAPDH served as protein loading control. 