(B) Immunoblot analysis of the immunoprecipitated HA-SOX9 or FLAG- FBW7α and their pull-down products. The corresponding Western blotting from the whole cell extract (WCE) of the transfected HEK293 showed the levels of exogenous HA-SOX9 or FLAG-FBW7α proteins in the total input. Cells were treated with 10 µM MG132 for 4 hours prior to harvesting for the immunoprecipitation. Blots are representative from 3 independent experiments. 