A. Sp1 proteins were pulled down from lysates of A549-Vec, A549-CUG2, BEAS-Vec, and BEAS-CUG2 cells in the absence or presence of TGF-β1 using an anti-Sp1 antibody. Smad2/3 proteins from the immunoprecipitates were detected with an anti-Smad2/3 antibody. B. Smad2/3 proteins were pulled down from lysates of A549-Vec, A549-CUG2, BEAS-Vec, and BEAS-CUG2 cells in the absence or presence of TGF-β1 using an anti-Smad2/3 antibody. Sp1 proteins from the immunoprecipitates were detected with an anti-Sp1 antibody. C, D. ChIP assays were performed with A549-Vec, A549-CUG2, BEAS-Vec, and BEAS-CUG2 cells. Chromatin fragments were pulled down with anti-Sp1, Smad2/3 antibodies or IgG as a control. Semi-quantitative PCRs were performed using specific CUG2 or TGF-β promoter primers. The assay was repeated twice.