E1A but not an E1A deletion mutant (ΔE1A) transduction blocked COX-2 expression and p300 binding to COX-2 promoter in HFb and RAW 264.7 cells. (A-D) Protein levels (A,C) and promoter activities (B,D) in PMA-treated HFb without p300 transfection and with p300 transfection (C-D). (E-H) COX-2 protein levels (E,G) and promoter activities (F,H) in LPS-treated RAW 264.7 cells without (E-F) and with (G-H) p300 transduction. (I) The binding of p300 to a COX-2 versus control probe. Co indicates a control probe; and COX-2, the COX-2 probe. In panels A, C, E, G, and I, the top panel shows a representative blot and the bottom panel shows mean ± SEM of the densitometry from 3 experiments. Other bars also denote mean ± SEM of 3 experiments.