Fig. 3

Comparative activity of human iNOS promoter of different length in A549 cells

The activity of different length constructs of human iNOS promoters coupled to a luciferase reporter gene was measured following transfection and cytokine activation as described in Materials and Methods. Results from non-activated cells are presented as open bars and cytokine-activated A549 cells as solid bars. A 1500-bp murine promoter was also tested. Equal numbers of cells were transfected with the constructs and luciferase activity was quantified after 8 hr of cytokine treatment. Inset shows the time course of luciferase activity in activated A549 cells with both the human and murine iNOS promoters. The luciferase activity was quantified at 8 and 24 hr postactivation and data are presented as the percentage increase (log scale) over that found in nonactivated cells. Activity of both the human (solid line) and the murine (dotted line) reporter constructs was maximal at 8 hr after cytokine activation of the cells.