During mammalian heart development, restricted myocardial Bmp2 expression is a key patterning signal for atrioventricular canal specification and the epithelial-mesenchyme transition that gives rise to the valves.
Functional studies in the mouse have shown that a Hey-Bmp2 regulatory circuit restricts Bmp2 expression to presumptive valve myocardium (atrioventricular canal and outflow tract).