3 ALTERNATIVELY SPLICED VARIANTS OF THE GENE CODING FOR THE HUMAN BONE MORPHOGENETIC PROTEIN-1

The human bone morphogenetic protein-1 was originally identified as a protein with the capacity to stimulate bone and cartilage growth in vi tro. Its gene sequence identified it as an alternatively spliced human homolog of the Drosophila dorsal-ventral patterning tolloid gene and suggested that it activates transforming growth factor-beta-like molec ules by proteolytic cleavage. Its expression pattern and its recently identified activity as a procollagen C proteinase, however, suggest th at it has a more general function in the early stages of embryogenesis , This view is strengthened by the previous observation of a third alt ernatively spliced isoform of the gene, called bone morphogenetic prot ein 1/His, We now show that the gene is expressed in three additional variants, leading to shorter and slightly modified C-termini. The thre e variants are preferentially expressed in placenta but show individua l differences in their expression profiles in other soft tissues.