Figure 2.

PIAS1 inhibits Stat1-mediated gene activation. (A) Luciferase reporter assays. Human 293 cells were transiently transfected with [(3x)Ly6] luciferase reporter construct together with empty expression vector, FLAG–Stat1 or various amounts of FLAG–PIAS1 vectors, alone or in combination as indicated. Cells were either treated or untreated with IFN-γ for 6 h. Shown is the fold increase after IFN-γ treatment. (B) Western blot analysis. Equal amounts of protein extracts from A were analyzed by immunoblot with anti-FLAG (Sigma).