Detection of betaig-H3, a TGFbeta induced gene, during cardiac development and its complementary pattern with periostin.

Regulation of normal cardiac development involves numerous transcription factors, cytoskeletal proteins, signaling molecules, and extracellular matrix proteins. These key molecular components act in concert to induce morphological changes essential for the proper development of a functional four-chambered heart. Growth factors such as BMPs and TGFbeta's play a role in migration, proliferation and differentiation during cardiac development and are important regulators of the extracellular matrix (ECM). Genes responsive to these morphogens are likely to play an equally significant role during cardiac development. Therefore, we sought to clone the chicken TGFbeta induced gene betaig-H3 and evaluate its spatio-temporal expression during heart morphogenesis. Our studies show by Northern analysis, whole mount and section in situ hybridization experiments that betaig-H3 is expressed primarily in the mesenchyme of the atrioventricular and outflow tract cushions and later in the right and left atrioventricular valve leaflets and supporting valve structures. The mRNA expression domains of betaig-H3 show a complementary pattern compared to that of its highly homologous relative, periostin.