Figure 3.

A: ETS family transcription factors up-regulate Bcl-xl promoter activity. I45 cells seeded in 96-well plates were cotransfected with Bcl-xl promoter p-XL and either GFP, ETS-1,−2, PU.1, Tel, or STAT expression vectors along with p-CMV-β-galactosidase. A p-GL2 luciferase vector was transfected as a negative control. Twenty-four hours after transfection, the cells were lysed, and the luciferase and β-galactosidase activities were measured with a luminometer. The luciferase activities were normalized to those of β-galactosidase, and the data shown are the average of triplicate determinations. This experiment was repeated twice. B: HGF stimulates Bcl-xl protein expression after ETS-2 and PU.1 transfection. I45 cells were seeded into six-well plates (10⁶ cells) and were transfected with ETS-2, PU.1 and GFP control expression vectors. The cells were then cultured under normal conditions, serum starvation, or serum starvation plus HGF (100 ng/ml). Bcl-xl expression was then determined by Western blot. Protein expression was quantified using an UN-SCAN-IT automated digitalized system (Silk Scientific Corporation, Orem, UT). RLU, relative light units.