(C) Snail mRNA expression is transiently induced by TGF-β2. The experiment in (B) was repeated, and this time, total RNAs were isolated from keratinocytes treated with TGF-β2 for the indicated times. RT-PCR was then used with (+) or without (–) reverse transcriptase (RT) and with primer sets specific for Snail and GAPDH mRNAs. Note that Snail mRNA expression also peaked at 2 h, paralleling Snail protein.