Chicken protogenin contains 1,187 amino acids and has an extracellular domain, followed by 4 immunoglobulin domains and 5 fibronectin type III domains. In situ hybridization showed that expression of chicken protogenin was prominent between embryonic days 1 and 3 and subsequently declined.
Transcripts localized to early mesodermal cells, the neuroepithelial cell layer of brain and trunk neural tube, the neural layer of retina, and in the epithelial somite and dermomyotome. By genomic sequence analysis, Toyoda et al. (2005) mapped the human PRTG gene to chromosome 15q21.3. They mapped the mouse Prtg gene to a region of chromosome 9C that shares homology of synteny with human chromosome 15q21.3.