title: Olfaction and odor discrimination are mediated by the C. elegans guanylyl cyclase ODR-1.
abstract: Animals in complex environments must discriminate between salient and uninformative sensory cues. Caenorhabditis elegans uses one pair of olfactory neurons called AWC to sense many different odorants, yet the animal can distinguish each odorant from the others in discrimination assays. We demonstrate that the transmembrane guanylyl cyclase ODR-1 is essential for responses to all AWC-sensed odorants. ODR-1 appears to be a shared signaling component downstream of odorant receptors. Overexpression of ODR-1 protein indicates that ODR-1 can influence odor discrimination and adaptation as well as olfaction. Adaptation to one odorant, butanone, is disrupted by ODR-1 overexpression. Olfactory discrimination is also disrupted by ODR-1 overexpression, probably by overproduction of the shared second messenger cGMP. We propose that AWC odorant signaling pathways are insulated to permit odor discrimination.
authors.affiliation: Howard Hughes Medical Institute, Department of Anatomy, University of California, San Francisco 94143, USA.
authors.forename: N D
authors.initials: ND
authors.lastname: L'Etoile
authors.forename: C I
authors.initials: CI
authors.lastname: Bargmann
mesh_terms: D000222:Adaptation, Physiological / Q000502:physiology; D000818:Animals; D030801:Animals, Genetically Modified; D001483:Base Sequence; D001522:Behavior, Animal / Q000502:physiology; D001547:Benzaldehydes; D002074:Butanones; D017173:Caenorhabditis elegans / Q000235:genetics*; D029742:Caenorhabditis elegans Proteins; D002462:Cell Membrane / Q000737:chemistry / Q000201:enzymology; D002628:Chemoreceptor Cells / Q000502:physiology; D004193:Discrimination Learning / Q000502:physiology; D005110:Extracellular Space / Q000737:chemistry; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D006162:Guanylate Cyclase / Q000378:metabolism*; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000502:physiology; D009812:Odorants; D018034:Olfactory Receptor Neurons / Q000737:chemistry / Q000201:enzymology; D000439:Pentanols; D017434:Protein Structure, Tertiary; D018035:Receptors, Odorant / Q000502:physiology*; D015398:Signal Transduction / Q000502:physiology; D012903:Smell / Q000502:physiology*
chemical_list: D001547:Benzaldehydes; D002074:Butanones; D029742:Caenorhabditis elegans Proteins; D000439:Pentanols; D018035:Receptors, Odorant; C110666:odr-3 protein, C elegans; C029683:isopentyl alcohol; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D020962:Heterotrimeric GTP-Binding Proteins; D006162:Guanylate Cyclase