title: Farnesol-detecting olfactory neurons in Drosophila.
abstract: We set out to deorphanize a subset of putative Drosophila odorant receptors expressed in trichoid sensilla using a transgenic in vivo misexpression approach. We identified farnesol as a potent and specific activator for the orphan odorant receptor Or83c. Farnesol is an intermediate in juvenile hormone biosynthesis, but is also produced by ripe citrus fruit peels. Here, we show that farnesol stimulates robust activation of Or83c-expressing olfactory neurons, even at high dilutions. The CD36 homolog Snmp1 is required for normal farnesol response kinetics. The neurons expressing Or83c are found in a subset of poorly characterized intermediate sensilla. We show that these neurons mediate attraction behavior to low concentrations of farnesol and that Or83c receptor mutants are defective for this behavior. Or83c neurons innervate the DC3 glomerulus in the antennal lobe and projection neurons relaying information from this glomerulus to higher brain centers target a region of the lateral horn previously implicated in pheromone perception. Our findings identify a sensitive, narrowly tuned receptor that mediates attraction behavior to farnesol and demonstrates an effective approach to deorphanizing odorant receptors expressed in neurons located in intermediate and trichoid sensilla that may not function in the classical "empty basiconic neuron" system.
authors.affiliation: Departments of Pharmacology and Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390, and Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
authors.forename: David S
authors.initials: DS
authors.lastname: Ronderos
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Lin
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Potter
authors.forename: Dean P
authors.initials: DP
authors.lastname: Smith
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal / Q000502:physiology; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000033:anatomy & histology / Q000502:physiology*; D005204:Farnesol; D005260:Female; D017952:Ganglia, Invertebrate / Q000166:cytology / Q000502:physiology; D008297:Male; D008565:Membrane Proteins / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000502:physiology; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000502:physiology*; D018035:Receptors, Odorant / Q000235:genetics / Q000502:physiology*; D012903:Smell / Q000502:physiology
chemical_list: D029721:Drosophila Proteins; D008565:Membrane Proteins; D009419:Nerve Tissue Proteins; C588414:Or83c protein, Drosophila; D018035:Receptors, Odorant; C106308:sensory neuron membrane protein 1; D005204:Farnesol
keywords: behavior; empty neuron; intermediate sensilla; olfaction; orphan receptor; receptor mutant