FIG. 5.

IL-4 decreases CBP binding to the involucrin promoter. HaCat cells were treated with IL-4 (20 ng/mL) or vehicle for 24 h. Chromatin immunoprecipitation assay was performed to study CBP binding to the involucrin promoter using an anti-CBP antibody (A). Data were quantified by real-time PCR and PCR products were sequenced. Values are expressed as the mean ± SEM (n = 3). *P < 0.05 versus vehicle. HaCat cells were incubated in 1% charcoal–dextran-treated fetal bovine serum (DMEM) for 24 h and then treated with IL-4 (20 ng/mL) or vehicle in the serum-free medium for 20 min. Coimmunoprecipitation was performed to study CBP interaction with Stat6 as described in Materials and Methods section (B). The experiment was repeated three times.