Probably involved in bone morphogenetic protein (BMP)-mediated cardiac-specific gene expression. Binds to BMP response element (BMPRE) DNA sequences within cardiac activating regions. More abundant in stomach and small intestine, lower levels in heart, lung and spleen. Very low levels in liver and ovary. Initially transcribed in the cardiac crescent prior to formation of the primordial heart tube. Following formation of the primitive heart, present in both endocardium and myocardium as well as in other lateral plate derivatives. Also transcribed in the primitive embryonic gut and in late stage embryos is sequentially up-regulated in distinct segments of gastrointestinal epithelia as they undergo terminal differentiation.