Novel Neuropeptide Y Y2-Like Receptor Subtype in Zebrafish and Frogs Supports Early Vertebrate Chromosome Duplications

Abstract

The Y receptors comprise a family of G-protein coupled receptors with neuropeptide Y-family peptides as endogenous ligands. The Y receptor family has five members in mammals and evolutionary data suggest that it diversified in the two genome duplications proposed to have occurred early in vertebrate evolution. If this theory holds true, it allows for additional family members to be present. We describe here the cloning, pharmacological characterization, tissue distribution, and chromosomal localization of a novel subtype of the Y-receptor family, named Y7, from the zebrafish. We also present Y7 sequences from rainbow trout and two amphibians. The new receptor is most similar to Y2, with 51-54% identity. As Y2 has also been cloned from some of these species, there clearly are two separate Y2-subfamily genes. Chromosomal mapping in zebrafish supports origin of Y7 as a duplicate of Y2 by chromosome duplication in an early vertebrate. Y7 has probably been lost in the lineage leading to mammals. The pharmacological profile of the zebrafish Y7 receptor is different from mammalian Y2, as it does not bind short fragments of NPY with a high affinity. The Y7 receptor supports the theory of early vertebrate genome duplications and suggests that the Y family of receptors is a result of these early genome duplications.

Birth and death of neuropeptide Y receptor genes in relation to the teleost fish tetraploidization

“…The Acba Y 1 sequence was extended in the 5′ direction using the inverse PCR technique described earlier (Salaneck et al, 2003). BLAST searches using the human NPY receptor sequences and previously identified Danio rerio sequences (Lundell et al, 1997;Ringvall et al, 1997;Starback et al, 1999;Fredriksson et al, 2004;Fredriksson et al, 2006) were used to make a preliminary survey of the NPY receptor repertoire in the fully sequenced genomes of Danio rerio, Oryzias latipes, Tetraodon nigroviridis, Takifugu rubribes and Gasterosteus aculeatus (see Supplementary Table 2). In D. rerio the sequence for Y 1 was obtained by PCR with specific primers based on the predicted coding sequence of the Y 1 sequence found in the zebrafish genome database and cloned into TOPO vector and sequenced as described above.…”

Interaction of NPY compounds with the rat glucocorticoid-induced receptor (GIR) reveals similarity to the NPY–Y2 receptor

“…The Y 1 , Y 2 , Y 3 , Y 5 and Y 7 receptors bind NPY with sub-nanomolar affinities [6,15] in contrast to rGIR (13 nM). The question arises whether NPY can bind rGIR under physiological conditions.…”

Stimulatory effects of neuropeptide Y on the growth of orange-spotted grouper (Epinephelus coioides)

“…In addition, studies have showed that fish NPY receptors are expressed not only in brain but also in peripheral tissues such as eye, intestine and the gastrointestinal (GI) tract [21,22,33]. To test the physiological functions of NPY in orange-spotted grouper, synthetic gNPY with different doses were directly sprayed on the surface of ordinary commercial pellet feed and used as daily diets to feed to orange-spotted grouper.…”