Figure 1

Smad3-dependent Ha-Ras activation of COL1A2 (human pro-α2 (I) collagen gene). (A) Luciferase activity (expressed as fold induction over control sample) of the COL1A2 promoter transiently co-transfected with plasmids expressing Ha-Ras, ca-Ras or DN-Ras in quiescent (human dermal fibroblast) hDF cultures (B) Western blot analyses of recombinant Ha-Ras, ca-Ras and DN-Ras levels in hDF cells (n = 3 per each sample) using anti-Ha-Ras antibodies. (C) Luciferase activity (expressed as fold induction over control sample) of wild-type and TbRE [transforming growth factor-β (TGFβ)-responsive element] mutated COL1A2 promoter constructs transiently co-transfected in quiescent hDF cultures with the indicated combinations of ca-Ras expressing plasmid or the DN-Smad3 expression vector; cells stimulated with recombinant TGFβ1 (2 ng/mL) served as a positive control. (D) Western blot analysis of recombinant DN-Smad3 levels in hDF cells (n = 3 per each sample) using anti-Smad3 antibodies. Luciferase values in panels A and C represent the average of three independent transfections each performed in duplicate. Error bars signify ± standard deviation and asterisks indicate statistically significant differences (P < 0.05).