Bone cells derived from a variety of animal species including human, bovine, ovine and rodent, and of varying developmental ages, have been utilized to: 1) study the biosynthesis and deposition of extracellular matrix proteins such as collagen, osteonectin, bone proteoglycans and other bone proteins, and alterations of matrix production in disease states such as Osteogenesis Imperfecta; 2) study the responsiveness of the cells to a variety of pharmacological factors (such as calcium); 3) elucidate the production of and interaction with growth factors (such as TGF-beta, insulin-like growth factors and platelet-derived growth factors); 4) study the potential function of bone matrix proteins through the use of assays and the use of anti-sense DNA to inhibit specific protein synthesis; and 5) serve as a source of mRNA and DNA for studies of the proteins at the genomic level in collaboration with Drs. Marian F. Young and Larry W. Fisher.