Transcripts for two members of the transforming growth factor-beta superfamily BMP-3 and BMP-7 are expressed in developing rat embryos.

Bone morphogenetic protein-3 (BMP-3) and BMP-7 are members of the transforming growth factor beta superfamily that have been implicated in the formation of cartilage and bone. Using in situ hybridization, we localized mRNAs for BMP-3 and BMP-7 during organogenesis in rats. Both mRNAs were expressed in a variety of cells, in particular, in the developing hair follicle, tooth, kidney, and lung tissues, in which reciprocal epithelial-mesenchymal interactions are essential. In some tissues, the distribution of BMP-3 and BMP-7 mRNAs overlapped. In other tissues, the patterns of expression were quite different. Moreover, the site of expression of the transcripts changed from one cell type to another during organogenesis. These results suggest that BMP-3 and BMP-7 play important roles in organogenesis and that the differential patterns of their expression might reflect their distinct roles in embryogenesis.