The purpose of this project is to determine the structure of proteoglycans as well as to understand the role that they play in the function of tissues and during developmental events. We have been using immunology, peptide mapping and molecular biology to characterize the core protein of proteoglycans from basement membrane. Basement membrane proteoglycans from EHS tissue consists of a MW = 4000,000 core protein 3 heparan sulfate side chains attached to one end. We have cloned and sequenced more than 60% (7Kb of our 12KB total) of the core protein. Distinct structural domains have been identified and should lead to more studies on function of this macromolecule. Using expression reactors containing certain regions of the cartilage proteoglycan, we have determined portion binds to hyaluronic acid.