Identification of response elements involved in IL1β-mediated induction of CD55 expression. A, schematic illustration of the positions of point mutations created in NF-κB binding sites and a CRE binding site on the CD55 promoter. B to D, Huh7 cells were transfected with either CD55Δ-395 (B), CD55Δ-480 (C), or CD55Δ-605 (D) by using the GenePorter3000 transfection reagent. Twenty-four hours after transfection, cells were treated with either vehicle or 10 μM DiMNF for 1 h followed by 24-h treatment with 10 ng/ml of IL1β. Luciferase activity was measured and normalized to β-galactosidase activity. Data represent mean relative luciferase units ± S.E.M. fold induction relative to control. E, Hep3B cells targeted with either control or RelA/p65-specific siRNA were incubated with vehicle or 10 μM DiMNF for 1 h before treatment with 10 ng/ml of IL1β for 24 h, and CD55 mRNA expression was measured by quantitative real-time PCR. Data represent mean mRNA expression level ± S.E.M. normalized to constitutively expressed ribosomal L13 mRNA. Statistical significance is indicated: ***, p < 0.001.