GATA4 and cardiomyopathy: Based on the effects of Bnip3 overexpression on p300 and myocyte morphology in vitro, and the increased levels of p300 and acetylated GATA4 in Bnip3-TG mice (Fig 9), we hypothesized that enhanced activity of p300/GATA4 in Bnip3-TG mice contributes to the progressive cardiomyopathy described in Fig 7.