Genome wide survey of G protein-coupled receptors in <it>Tetraodon nigroviridis</it>

• Main Authors: Sowdhamini Ramanathan, Metpally Raghu
• Format: Article
• Language: English
• Published: BMC 2005-07-01
• Series: BMC Evolutionary Biology
• Online Access: http://www.biomedcentral.com/1471-2148/5/41

<p>Abstract</p> <p>Background</p> <p>The G-protein-coupled receptors (GPCRs) constitute one of the largest and most ancient superfamilies of membrane proteins. They play a central role in physiological processes affecting almost all aspects of the life cycle of an organism. Availability of the complete sets of putative members of a family from diverse species provides the basis for cross genome comparative studies.</p> <p>Results</p> <p>We have defined the repertoire of GPCR superfamily of <it>Tetraodon </it>complement with the availability of complete sequence of the freshwater puffer fish <it>Tetraodon nigroviridis</it>. Almost all 466 <it>Tetraodon </it>GPCRs (Tnig-GPCRs) identified had a clear human homologue. 189 putative human and <it>Tetraodon </it>GPCR orthologous pairs could be identified. <it>Tetraodon </it>GPCRs are classified into five GRAFS families, by phylogenetic analysis, concurrent with human GPCR classification.</p> <p>Conclusion</p> <p>Direct comparison of GPCRs in <it>Tetraodon </it>and human genomes displays a high level of orthology and supports large-scale gene duplications in <it>Tetraodon</it>. Examples of lineage specific gene expansions were also observed in opsin and odorant receptors. The human and <it>Tetraodon </it>GPCR sequences are analogous in terms of GPCR subfamilies but display disproportionate numbers of receptors at the subfamily level. The teleost genome with its expanded set of GPCRs provides additional and interesting comparators to study both evolution and function of these receptors.</p>