GDF-7 belongs to the TGF-β superfamily of growth and differentiation factors. It is expressed selectively by roof plate cells that are located in the developing embryonic central nervous system, and has been shown to influence the neuronal identity of cells within the central nervous system. GDF-7 has also been implicated in the formation, maintenance, and repair of certain cartilage and ligament tissue. Recombinant human GDF-7 is a 28 kDa disulfide linked homodimer containing two 129 amino acid residues.