Recombinant Chicken Netrin-1 Protein

Chicken Netrin-1 is the prototypical member of an ever-expanding, laminin-related family of axon-guidance molecules collectively referrred to as netrins (netr is Sanskrit for “one who guides”). The molecule’s cDNA encodes a 606 amino acid (aa) protein precursor that has structural similarity to the N-terminus of the B2 or gamma-chain of laminin. It contains one 250 aa type VI globular domain, three type V (~55 aa) cysteine/glycine rich EGF repeats, and one unique 140 aa “C” domain that binds heparin. Chick Netrin-1 shares 78% aa identity with chicken Netrin-2 and 86% aa identity with mouse and human Netrin-1. Although only two chick netrins are known, the number of known mammalian netrins is increasing. Human and mouse Netrin-3/NTN-2L, and a mouse Netrin-4, that shares homology with the B1 or beta-chain of laminin, have been reported. Cells reported to express Netrin-1 in the embryo include cells of the spinal cord floor plate and somite, cells of the ganglionic eminence, and cells of the floor plate of the met- and caudal mesencephalon. In the adult, neurons of the thalamus, neocortex, and hippocampus, plus Schwann cells, osteoclasts and osteoblasts all reportedly produce Netrin-1. The DCC (deleted in colorectal cancer) gene product as well as the UNC5 family of receptors and the adenosine A2b receptor have been proposed to be functional receptors for Netrin-1.