%0 Journal Article
%T The repertoire of olfactory C family G protein-coupled receptors in zebrafish: candidate chemosensory receptors for amino acids
%A Tyler S Alioto
%A John Ngai
%J BMC Genomics
%D 2006
%I BioMed Central
%R 10.1186/1471-2164-7-309
%X Using genome database mining and other informatics approaches, we identified and characterized the repertoire of 54 intact "V2R-like" olfactory C family GPCRs in the zebrafish. Phylogenetic analysis ¨C which also included a set of 34 C family GPCRs from fugu ¨C places the fish olfactory receptors in three major groups, which are related to but clearly distinct from other C family GPCRs, including the calcium sensing receptor, metabotropic glutamate receptors, GABA-B receptor, T1R taste receptors, and the major group of V2R vomeronasal receptor families. Interestingly, an analysis of sequence conservation and selective pressure in the zebrafish receptors revealed the retention of a conserved sequence motif previously shown to be required for ligand binding in other amino acid receptors.Based on our findings, we propose that the repertoire of zebrafish olfactory C family GPCRs has evolved to allow the detection and discrimination of a spectrum of amino acid and/or amino acid-based compounds, which are potent olfactory cues in fish. Furthermore, as the major groups of fish receptors and mammalian V2R receptors appear to have diverged significantly from a common ancestral gene(s), these receptors likely mediate chemosensation of different classes of chemical structures by their respective organisms.The vertebrate olfactory system receives and decodes sensory information from a myriad chemical cues. The first step in this process is the recognition of these cues by receptors expressed by the primary sensory neurons in the olfactory epithelium (reviewed in refs. [1,2]). Receptor-mediated activity within the population of olfactory sensory neurons is then interpreted by the brain to identify the molecular nature of the odorant stimulus. A large multigene family thought to encode odorant receptors was initially identified in the rat [3] and belong to what is now referred to as the "OR" superfamily of odorant receptors (reviewed in [4]). The predicted structure of these recept
%U http://www.biomedcentral.com/1471-2164/7/309