Protogenin: ProductsProtogenin (Early/proto in expression, neogenin-like; also Prtg) is a 130 kDa (predicted), type I transmembrane member of the DCC/Neogenin family of proteins. It is expressed in mouse presomitic mesoderm, paraxial mesoderm, and neural tube. Mature mouse protogenin is 1168 amino acids (aa) in length. It contains a 920 aa extracellular domain (ECD) (aa 24 - 943) plus a 224 aa cytoplasmic region. The ECD contains four consecutive Ig-like domains (aa 24 - 405), followed by five sequential fibronectin type III domains (aa 413 - 908). The ECD of mouse protogenin shares 98%, 87% and 93% aa identity with the ECD of rat, chick and human protogenin, respectively.