FIG. 4.

TGFβ1- and IL-1β-induced native transcription factor binding to the human COX-2 promoter in F-NL and F-IPF. Confluent and serum-starved F-NL and F-IPF cells in 150-cm² flasks were incubated with TGF-β1 (2 ng/ml) (A to C) or IL-1β (1 ng/ml) (D to F) for the times indicated. The protein-DNA complexes were cross-linked by formaldehyde treatment, and chromatin pellets were extracted and sonicated. The transcription factors NF-κB (A and D), C/EBPβ (B and E), and CREB-1 (C and F) were immunoprecipitated with specific antibodies, and the associated COX-2 promoter DNA was amplified by real-time PCR as described in Materials and Methods. The results are normalized relative to the input control and are the means ± SEM of data for three separate F-NL and F-IPF cell lines analyzed in duplicate.