Cloning of the chick BMP1/Tolloid cDNA and expression in skeletal tissues

The astacin-related metalloproteases Bone Morphogenetic Protein-1 (BMP1) an d Tolloid possess multiple functions in the maturation of extracellular mat rices containing fibrillar collagens. We are interested in developing an in -vitro model system to study the role of BMP1 and Tolloid in chondrocytes a nd osteoblasts. Cloning of the cDNAs for chick BMP1 and Tolloid reveals tha t the two gene products are more than 80% identical to their human and mous e homologs and are similarly derived from the same genetic locus. Anti-BMP1 /Tolloid antibodies have been developed, and detect two proteins of 80 and 116 kDa. Chick BMP1 and Tolloid message and proteins are found in a variety of embryonic and juvenile tissues, including chondrocytes and osteoblasts. Tolloid message and protein are generally less abundant than BMP1 message; this discrepancy is greatest in growth plate chondrocytes. Tolloid protein is more tightly bound than BMP1 to the extracellular matrix produced by cu ltured osteoblasts, The Chordin gene is also expressed in chondrocytes and osteoblasts, suggesting that BMP1 and Tolloid influence BMP signaling as we ll as matrix maturation during skeletogenesis. (C) 2000 Elsevier Science B. V. All rights reserved.