Expression of bone morphogenetic protein-10 mRNA during chicken heart development.

In this communication we describe the expression pattern of BMP10 mRNA during cardiac development in chickens. BMP10 is considered an important factor in the regulation of cardiac growth and trabeculation in the murine embryo. We identified chicken Ests, which are similar to mouse and human BMP10 in the UMIST database. The cDNA clone that contained most sequences was obtained, verified by sequence analysis, and used to determine the spatiotemporal pattern of gene expression. BMP10 mRNA is initially expressed at HH10 in the myocardium of the arterial pole of the heart tube, anterior to the interventricular groove. Between HH14 and HH22, BMP10 mRNA becomes broadly expressed in the outflow tract, the distal part of the inflow tract, and the trabeculated part of the developing ventricles and atria. From HH31 onward, BMP10 mRNA expression decreases in the ventricular myocardium by first disappearing from the compact myocardium and then from the tips of the trabecules. At HH44, BMP10 mRNA is expressed only in the trabeculated myocardium of the atria and the endocardium of the ventricles. The observed expression pattern of BMP10 mRNA suggests that it may play a role in regulating the formation of the ventricular wall and trabecules.