Wild-type p300 but not ΔHAT increased p300 binding to COX-2 promoter in HFb. (A) Effect of p300 or ΔHAT overexpression on p300 binding to a biotinylated COX-2 promoter probe analyzed by a streptavidin-agarose pulldown assay. C indicates a control probe; and COX-2, the COX-2 probe. (B) Influence of wild-type p300 versus ΔHAT transfection on p300 binding to a chromatin COX-2 promoter region. Chromatins were immunoprecipitated with a polyclonal p300 antibody and COX-2 promoter region was analyzed by PCR. The left column of each panel shows DNA input. A nonimmune rabbit normal IgG was included with each stimulus as control. Only the LPS-treated cells are shown. In all panels, the top panel shows a representative of 3 experiments and the bottom panel shows mean ± SEM of the densitometry from 3 experiments.