Figure 4. The effect of TGF-β1 on βIGH3 promoter fragments in the A549 cell line

A549 cells were transiently transfected with the -1000 to -1 or -336 to -1 fragment luciferase constructs. With the addition of 20 ng/ml TGF-β1, the promoter activity of the -1000 to -1 fragment was upregulated by 2.3 times, whereas no significant effect was observed with the addition of 2 ng/ml TGF-β1. The data demonstrated that the 1 Kb fragment responded to TGF-β1 in a dose-dependent manner. Data were expressed as an n-fold increase of normalized luciferase activities over the baseline. Each transfection experiment was tested in quadruplicate in each experiment and results from two experiments were pooled for statistical analysis. Error bars represent standard error of the effect.