(C) Western blotting of HEK293 endogenous SOX9 proteins 24 hours following forced expression of 100, 250, 500, and 1000 ng of plasmid expressing FLAG-FBW7α. Changes in SOX9 protein level in the representative blots were analysed relative to GAPDH using ImageJ. The set of blots shown is representative from 3 independent experiments. 