Fasciculation and elongation protein zeta-2 is an ortholog of the C. elegans unc-76 gene, which is necessary for normal axonal bundling and elongation within axon bundles. Other orthologs include the rat gene that encodes zygin II, which can bind to synaptotagmin.The C. elegans gene unc-76 ('unc' for 'uncoordinated') is necessary for normal axonal bundling and elongation within axon bundles. By searching an EST database with the UNC-76 sequence, Bloom and Horvitz identified 2 human genes with sequence similarity to unc-76; they named these novel genes FEZ1 and FEZ2. The longest FEZ2 EST identified encodes a deduced 251-amino acid partial protein lacking N-terminal sequence. FEZ2 shares 49% and 34% amino acid sequence identity with FEZ1 and UNC-76, respectively, in the regions of overlap.