FIG. 2.

Differential effects of GATA4 on myocardin-dependent transcription. COS cells were transiently transfected with luciferase reporter plasmids controlled by (A) the ANF promoter or a mutant promoter lacking the two GATA4 binding sites, (B) the SM22 promoter, or (C) four copies of the SM22 CArG box and the indicated amounts (in nanograms) of myocardin and GATA4 expression vectors. Luciferase activity was assayed and is expressed as fold activation above the level of expression of the reporter gene alone.