Meeting Abstract
Chemoreception is necessary for the survival and reproduction of all organisms. Thus, the molecular mechanisms of chemoreception are of vital importance to the evolution of a species. These mechanisms help mediate an organism’s interaction with its environment, including the detection of potentially harmful compounds. While much is known about the identity of chemical defenses produced by many prey species, not much is known about the chemoreception mechanisms used by predators to detect prey chemical defenses. In one system, the marine generalist Thalassoma bifasciatum (bluehead wrasse) and the model organism Danio rerio (zebrafish) are both deterred from eating foods laced with triterpene glycoside defense compounds produced by the marine sponge Erylus formosus. We have identified a small membrane bound co-receptor, known as RL-TGR, which is involved in this system of aversive chemoreception in both bluehead wrasse and zebrafish. In addition, other species of fish have RL-TGR orthologs in their genomes. We seek to characterize the mechanism of action of this novel chemoreceptor by localizing its expression in zebrafish and bluehead wrasse and mapping the ligand binding site of RL-TGR using mutagenesis studies. We also seek to determine the breadth of RL-TGR signaling in various fish species by utilizing bioinformatic approaches. A better understanding of this mechanism will give insight into the evolution of aversive chemoreception in fish and its potential role in speciation events.
