The vertebrate olfactory system utilizes odorant receptors to receive and discriminate thousands of different chemical stimuli. An understanding of how these receptors encode information about an odorant's molecular structure requires a characterization of their ligand specificities. We employed an expression cloning strategy to identify a goldfish odorant receptor that is activated by amino acids-potent odorants for fish. Structure-activity analysis indicates that the receptor is preferentially tuned to recognize basic amino acids. The receptor is a member of a multigene family of G protein-coupled receptors, sharing sequence similarities with the calcium sensing, metabotropic glutamate, and V2R class of vomeronasal receptors. The ligand tuning properties of the goldfish amino acid odorant receptor provide information for unraveling the molecular mechanisms underlying olfactory coding.
Bibliographical noteFunding Information:
This research was supported by the National Institute on Deafness and Other Communication Disorders (NIDCD) and the Office of Naval Research (J. N.), and from the National Science Foundation (P. W. S.). D. M. L. was supported by a postdoctoral fellowship from the NIDCD. J. N. was a Pew Scholar in the Biomedical Sciences. A. H. D. is a Burroughs Wellcome Fellow of the Life Sciences Research Foundation. We thank L. Hanson for graciously sharing unpublished data, T. Livelli for HEK 293 cells, H. Amrein for the 608RX-2.2L expression vector, L. Jan and J. Adelman for GIRK cDNAs, R. Reed for the G olf cDNA, E. Liman for pGEMHE, L. Brunet for help with molecular biology, T. Finger for helpful discussions, K. Harris for help with sequence analysis, R. Harris for assistance with electrophysiology, and members of the Ngai and Isacoff labs for their invaluable advice over the course of this project.