FIG. 5.

C/EBPβ transactivates the IGF-I promoter 1. The IGF-I promoter-reporter constructs IGF1711b-Luc, 4xHS3D-Luc, and 4xHS3D_mut-Luc were cotransfected with either empty pcDNA3.1 or pcDNA3.1-C/EBPβ into HepG2 cells. The cells were serum starved for 24 h, lysates were prepared, and luciferase activity was analyzed. The luciferase data were normalized to total protein and are the average of two independent experiments, each performed in triplicate with standard errors indicated. Statistical analysis of the data was performed using Student's unpaired t test (**, P < 0.01).