title: Neuropeptide Y-family peptides and receptors in the elephant shark, Callorhinchus milii confirm gene duplications before the gnathostome radiation.
abstract: We describe here the repertoire of neuropeptide Y (NPY) peptides and receptors in the elephant shark Callorhinchus milii, belonging to the chondrichthyans that diverged from the rest of the gnathostome (jawed vertebrate) lineage about 450 million years ago and the first chondrichthyan with a genome project. We have identified two peptide genes that are orthologous to NPY and PYY (peptide YY) in other vertebrates, and seven receptor genes orthologous to the Y1, Y2, Y4, Y5, Y6, Y7 and Y8 subtypes found in tetrapods and teleost fishes. The repertoire of peptides and receptors seems to reflect the ancestral configuration in the predecessor of all gnathostomes, whereas other lineages such as mammals and teleosts have lost one or more receptor genes or have acquired 1-2 additional peptide genes. Both the peptides and receptors showed broad and overlapping mRNA expression which may explain why some receptor gene losses could take place in some lineages, but leaves open the question why all the known ancestral receptors have been retained in the elephant shark.
authors.affiliation: Department of Neuroscience, Uppsala University, Uppsala, Sweden. Tomas.Larsson@neuro.uu.se
authors.forename: Tomas A
authors.initials: TA
authors.lastname: Larsson
authors.forename: Boon-Hui
authors.initials: BH
authors.lastname: Tay
authors.forename: Görel
authors.initials: G
authors.lastname: Sundström
authors.forename: Robert
authors.initials: R
authors.lastname: Fredriksson
authors.forename: Sydney
authors.initials: S
authors.lastname: Brenner
authors.forename: Dan
authors.initials: D
authors.lastname: Larhammar
authors.forename: Byrappa
authors.initials: B
authors.lastname: Venkatesh
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002875:Chromosomes / Q000235:genetics; D030541:Databases, Genetic; D020440:Gene Duplication; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000737:chemistry / Q000235:genetics*; D010802:Phylogeny; D017476:Receptors, Neuropeptide Y / Q000145:classification / Q000235:genetics*; D016415:Sequence Alignment; D012754:Sharks / Q000145:classification / Q000235:genetics* / Q000378:metabolism
chemical_list: D009478:Neuropeptide Y; D017476:Receptors, Neuropeptide Y