FIG. 2.

CBP augments the IFN-γ and CIITA activation of a class II promoter. (A) CAT activity from uninduced and IFN-γ-induced HeLa cells transfected with an Eα CAT plasmid was assayed in the absence or the presence of 1, 2, or 3 μg of a CBP-expressing plasmid. (B) CAT activity of the Eα CAT promoter in HeLa cells after introduction of CIITA (0.05 or 0.5 μg), CBP (4 μg), or both expression plasmids. (C) Potentiation of the action of CIITA by CBP requires the N-terminal activation domain of CIITA. CAT activity of the Eα CAT promoter in HeLa cells after introduction of the CIITA truncation Δ102 mutant (0.5 μg), CBP (4 μg), or both expression plasmids is shown.