Evolution of vertebrate opioid receptors
2008 (English)In: Proceedings of the National Academy of Science of the United States of America, ISSN 0027-8424, Vol. 105, no 40, 15487-15492 p.Article in journal (Refereed) Published
The opioid peptides and receptors have prominent roles in pain transmission and reward mechanisms in mammals. The evolution of the opioid receptors has so far been little studied, with only a few reports on species other than tetrapods. We have investigated species representing a broader range of vertebrates and found that the four opioid receptor types (delta, kappa, mu, and NOP) are present in most of the species. The gene relationships were deduced by using both phylogenetic analyses and chromosomal location relative to 20 neighboring gene families in databases of assembled genomes. The combined results show that the vertebrate opioid receptor gene family arose by quadruplication of a large chromosomal block containing at least 14 other gene families. The quadruplication seems to coincide with, and, therefore, probably resulted from, the two proposed genome duplications in early vertebrate evolution. We conclude that the quartet of opioid receptors was already present at the origin of jawed vertebrates approximately 450 million years ago. A few additional opioid receptor gene duplications have occurred in bony fishes. Interestingly, the ancestral receptor gene duplications coincide with the origin of the four opioid peptide precursor genes. Thus, the complete vertebrate opioid system was already established in the first jawed vertebrates.
Place, publisher, year, edition, pages
2008. Vol. 105, no 40, 15487-15492 p.
Chromosome, G protein-coupled receptor, gene duplication
Medical and Health Sciences
IdentifiersURN: urn:nbn:se:uu:diva-105035DOI: 10.1073/pnas.0805590105ISI: 000260360500050PubMedID: 18832151OAI: oai:DiVA.org:uu-105035DiVA: diva2:220366