FIGURE 4.

Snail1 and Twist mutually regulate their expression in NMuMG cells. Panels A and B, NMuMG cells expressing scrambled, or shRNAs specific for Snail1 or Twist1 were incubated with TGF-β for the indicated times; protein extracts were prepared or RNA was isolated and analyzed by Western blot (WB) (A) or qRT-PCR (B). Panels C and D, Twist1 RNA (C) and protein (D) were analyzed in RWP-1 or HT-29 M6 cells transfected with Snail1-HA or control plasmid. In panel E, NMuMG cells treated with TGF-β for 24 h when indicated, or RWP1 cells ectopically expressing Snail1 or control plasmid were supplemented with CHX to block protein synthesis. Protein extracts were prepared after the indicated times and analyzed by Western blot. The figure shows representative results (A and D) or the average ± range (B, C, and E) of two experiments performed.