GATA-4 belongs to a group of related finger proteins that recognize DNA sequences known as the GATA motif. GATA-4 is thought to function as an activator of transcription in the heart , gonads , primitive endoderm, and gut. GATA-4 RNA is first detected in embryonic tissue at the primitive streak stage in the visceral endoderm and precardiogenic mesoderm approximately 0.5 days before the appearance of transcripts encoding contractile proteins, such as the α- myosin heavy chain, myosin light chain and cTnC. A number of chimeras were obtained in which Gata4 + / + cells were limited by the visceral endoderm of the yolk sac and a small part of the anterior / posterior endoderm. Despite the absence of GATA-4 in all other cells, the development of the heart, anterior intestine, and surrounding tissues occurred normally. Therefore, expression of GATA-4 in the endoderm rather than in cardiogenic mesoderm is necessary for ventral morphogenesis .
Initially, GATA-4 expression is associated with the caudal end of the heart tube (tract inflow). Then its expression is enhanced along the entire length of the heart tube by 9-10 days. Expression of GATA-4 is interrupted suddenly in the distal part of the outflow tract. No GATA-4 expression was detected in the aortic sac or dorsal aorta. Therefore, the myocardium of the exit tract and arteries of the pharyngeal arches has a different embryonic origin. Small amounts of GATA-4 RNA were found in the head and pharyngeal arches of the mesoderm. GATA-4 mRNA is found in the heart of late fetuses and adults.
It has been suggested that GATA-4 can regulate genes important for epithelial function, such as the synthesis of VKM molecules.