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- Larsson, Tomas A., 1978-, et al.
(författare)
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Neuropeptide Y-family peptides and receptors in the elephant shark, Callorhinchus milii confirm gene duplications before the gnathostome radiation
- 2009
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Ingår i: Genomics. - : Elsevier BV. - 0888-7543 .- 1089-8646. ; 93:3, s. 254-260
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Tidskriftsartikel (refereegranskat)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.
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| 2. |
- Sundström, Görel, et al.
(författare)
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Characterization of the neuropeptide Y system in the frog Silurana tropicalis (Pipidae) : three peptides and six receptor subtypes
- 2012
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Ingår i: General and Comparative Endocrinology. - : Elsevier BV. - 0016-6480 .- 1095-6840. ; 177:3, s. 322-331
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Tidskriftsartikel (refereegranskat)abstract
- Neuropeptide Y and its related peptides PYY and PP (pancreatic polypeptide) are involved in feeding behavior, regulation of the pituitary and the gastrointestinal tract, and numerous other functions. The peptides act on a family of G-protein coupled receptors with 4-7 members in jawed vertebrates. We describe here the NPY system of the Western clawed frog Silurana (Xenopus) tropicalis. Three peptides, NPY, PYY and PP, were identified together with six receptors, namely subtypes Y1, Y2, Y4, Y5, Y7 and Y8. Thus, this frog has all but one of the ancestral seven gnathostome NPY-family receptors, in contrast to mammals which have lost 2-3 of the receptors. Expression levels of mRNA for the peptide and receptor genes were analyzed in a panel of 19 frog tissues using reverse transcriptase quantitative PCR. The peptide mRNAs had broad distribution with highest expression in skin, blood and small intestine. NPY mRNA was present in the three brain regions investigated, but PYY and PP mRNAs were not detectable in any of these. All receptor mRNAs had similar expression profiles with high expression in skin, blood, muscle and heart. Three of the receptors, Y5, Y7 and Y8, could be functionally expressed in HEK-293 cells and characterized with binding studies using the three frog peptides. PYY had the highest affinity for all three receptors (K(i) 0.042-0.34 nM). Also NPY and PP bound to the Y8 receptor with high affinity (0.14 and 0.50 nM). The low affinity of NPY for the Y5 receptor (100-fold lower than PYY) differs from mammals and chicken. This may suggest a less important role of NPY on Y5 in appetite stimulation in the frog compared with amniotes. In conclusion, our characterization of the NPY system in S. tropicalis with its six receptors demonstrates not only greater complexity than in mammals but also some interesting differences in ligand-receptor preferences.
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