Functional Characterization of Odorant Receptors

摘要

The goal of this research program was to enhance our understanding of themolecular mechanisms that underlie odor recognition. Odorant receptors are G-protein-linked receptors that couple binding of odorants to activation of adenylyl cyclase or phospholipase C. They show extensive sequence diversity in their transmembrane domains, especially the fourth and fifth transmembrane helices, referred to as the 'hypervariable odorant binding domain.' A chimeric receptor was constructed in which a cassette encoding the hypervariable odorant binding domain of rat odorant receptor I-15 was inserted in the human P2-adrenergic receptor. This construct was cloned in a eukaryotic expression vector and expressed in stably transfected cells. This system forms the basis for future structure/function studies on the interactions between odorants and this hypervariable odorant binding domain. We initiated two additional lines of research that can provide insights in odor recognition and its relation to odor-guided behavior. One approach utilizes avoidance behavior toward certain odorants displayed by Drosophila melanogaster. This organism is amenable to genetic, molecular biological, neuroanatomical and behavioral studies, allowing multidisciplinary studies. The other approach centers on recognition of pheromones that trigger reproductive behavior via the vomeronasal organ and characterization of the signal transduction pathways they activate.