Sense and antisense TGFβ3 mRNA levels correlate with cardiac valve induction

The formation of the valves in the heart is a spatially and temporally controlled process. A tissue interaction between the endothelium and its adjacent myocardium initiates the transformation of the endothelium into the mesenchymal precursors of the heart valve. One or more of the molecules implicated as critical for valve formation are members of the transforming growth factor β family of molecules. Presented here is a spatial and temporal analysis of TGFβ and TGFβ3 in the chick heart during valve formation. We show that TGFβ mRNA is concentrated in AV canal tissue where valve formation will occur, consistent with previous observations that TGFβ3 production is critical during valve formation. Additionally, an RNA complementary to TGFβ3 encoding mRNA is present in the heart. The temporally controlled appearance of RNA complementary to TGFβ3 suggests that this molecule may play a role in the regulation of TGFβ3 production in the heart. © 1992 Wiley‐Liss, Inc.