title: Response of Drosophila to wasabi is mediated by painless, the fly homolog of mammalian TRPA1/ANKTM1.
abstract: A number of repellent compounds produced by plants elicit a spicy or pungent sensation in mammals . In several cases, this has been found to occur through activation of ion channels in the transient receptor potential (TRP) family . We report that isothiocyanate (ITC), the pungent ingredient of wasabi, is a repellent to the insect Drosophila melanogaster, and that the painless gene, previously known to be required for larval nociception, is required for this avoidance behavior. A painless reporter gene is expressed in gustatory receptor neurons of the labial palpus, tarsus, and wing anterior margin, but not in olfactory receptor neurons, suggesting a gustatory role. Indeed, painless expression overlaps with a variety of gustatory-receptor gene reporters. Some, such as Gr66a, are known to be expressed in neurons that mediate gustatory repulsion . painless mutants are not taste blind; they show normal aversive gustatory behavior with salt and quinine and attractive responses to sugars and capsaicin. The painless gene is an evolutionary homolog of the mammalian "wasabi receptor" TRPA1/ANKTM1 , also thought to be involved in nociception. Our results suggest that the stinging sensation of isothiocyanate is caused by activation of an evolutionarily conserved molecular pathway that is also used for nociception.
authors.affiliation: Division of Biology 156-29, California Institute of Technology, Pasadena, California 91125, USA.
authors.forename: Bader
authors.initials: B
authors.lastname: Al-Anzi
authors.forename: W Daniel
authors.initials: WD
authors.lastname: Tracey
authors.forename: Seymour
authors.initials: S
authors.lastname: Benzer
mesh_terms: D000818:Animals; D001362:Avoidance Learning; D015220:Calcium Channels / Q000235:genetics; D002211:Capsaicin / Q000494:pharmacology; D029721:Drosophila Proteins / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D005247:Feeding Behavior; D005518:Food Preferences; D007473:Ion Channels / Q000187:drug effects / Q000235:genetics / Q000502:physiology*; D017879:Isothiocyanates / Q000494:pharmacology*; D008297:Male; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000235:genetics; D011984:Sensory Receptor Cells / Q000378:metabolism / Q000502:physiology; D000074025:TRPA1 Cation Channel; D013649:Taste / Q000502:physiology; D050051:Transient Receptor Potential Channels / Q000235:genetics
chemical_list: D015220:Calcium Channels; D029721:Drosophila Proteins; D007473:Ion Channels; D017879:Isothiocyanates; D009419:Nerve Tissue Proteins; D000074025:TRPA1 Cation Channel; C473350:TRPA1 protein, human; D050051:Transient Receptor Potential Channels; C474592:pain protein, Drosophila; C037152:isothiocyanic acid; D002211:Capsaicin