Molecular cloning of bone morphogenetic protein (BMP) gene from the planarian Dugesia japonica

BMP (Bone Morphogenetic Protein) acts as a morphogen for dorso-ventral patterning and organogenesis in both vertebrate and invertebrate development. A cDNA encoding BMP (named Djbmp) has been cloned and sequenced from the planarian Dugesia japonica. The mature form of DjBMP which was deduced from the cDNA sequence was composed of 114 amino acid residues. The position of seven cysteine residues of the mature DjBMP was highly conserved among the TGF-beta superfamily. DjBMP had high similarity to human BMP-2A (50% amino acid identity), BMP-4 (49%) and Drosophila decapentaplegic protein (48%), indicating that DjBMP belongs to DVR (decapentaplegic-Vg1-related) group. The expression pattern in intact and regenerating planarians revealed by whole mount in situ hybridization suggested that the DjBMP plays a role not only in dorso-ventral but also in mid-lateral body patterning.