FGF3 belongs to the FGF family, members of which act on cells of mesodermal and neuroectodermal origin. Originally designated int2, the FGF3 gene was initially identified as a protooncogene in mice. FGF3 plays an important role in the regulation of embryonic development, cell proliferation, and cell differentiation and is required for normal ear development. Heparan sulfate glycosaminoglycans function as co-receptors to increase the affinity between FGF3 and its receptors; FGFR1 and FGFR2. Human and mouse FGF3 are known to share 88% amino acid sequence identity. Recombinant Human FGF3 is a single polypeptide of 21 kDa.