Molecular cloning of 5-hydroxytryptamine (5-HT) type 1 receptor genes from the Japanese puffer fish, Fugu rubripes.

To characterize the structure of Fugu G-protein coupled receptor family and its evolutionary divergence, we have cloned and sequenced the Fugu 5-HT type 1 receptor genes by Polymerase Chain Reaction (PCR) with degenerate primers followed by phage library screening. The analysis of the deduced amino acid sequences showed that F1A alpha and F1A beta have the highest homology to the human 5-HT1A receptor (71.5% and 63.7%, respectively). Another clone, F1D, showed highest (70.5%) homology to the human type 1D receptor. The amino acid residues that are important for ligand binding have been conserved in these Fugu genes. The phylogenetic tree analysis suggests that the duplication event of the Fugu type 1A receptor may have occurred after the divergence of Fugu and the tetrapod lineage.