title: The Drosophila IR20a clade of ionotropic receptors are candidate taste and pheromone receptors.
abstract: Insects use taste to evaluate food, hosts, and mates. Drosophila has many "orphan" taste neurons that express no known taste receptors. The Ionotropic Receptor (IR) superfamily is best known for its role in olfaction, but virtually nothing is known about a clade of ∼35 members, the IR20a clade. Here, a comprehensive analysis of this clade reveals expression in all taste organs of the fly. Some members are expressed in orphan taste neurons, whereas others are coexpressed with bitter- or sugar-sensing Gustatory receptor (Gr) genes. Analysis of the closely related IR52c and IR52d genes reveals signatures of adaptive evolution, roles in male mating behavior, and sexually dimorphic expression in neurons of the male foreleg, which contacts females during courtship. These neurons are activated by conspecific females and contact a neural circuit for sexual behavior. Together, these results greatly expand the repertoire of candidate taste and pheromone receptors in the fly.
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Tong-Wey
authors.initials: TW
authors.lastname: Koh
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: He
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Srinivas
authors.initials: S
authors.lastname: Gorur-Shandilya
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Karen
authors.initials: K
authors.lastname: Menuz
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Nikki K
authors.initials: NK
authors.lastname: Larter
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA.
authors.forename: Shannon
authors.initials: S
authors.lastname: Stewart
authors.affiliation: Department of Molecular, Cellular and Developmental Biology, Yale University, New Haven, CT 06520, USA. Electronic address: john.carlson@yale.edu.
authors.forename: John R
authors.initials: JR
authors.lastname: Carlson
mesh_terms: D000818:Animals; D029721:Drosophila Proteins / Q000096:biosynthesis / Q000502:physiology*; D004331:Drosophila melanogaster; D005260:Female; D015870:Gene Expression; D008297:Male; D008969:Molecular Sequence Data; D009474:Neurons / Q000502:physiology; D011956:Receptors, Cell Surface / Q000502:physiology*; D043563:Receptors, Pheromone / Q000502:physiology*; D012727:Sex Characteristics; D012726:Sexual Behavior, Animal / Q000502:physiology; D013649:Taste / Q000502:physiology*
chemical_list: D029721:Drosophila Proteins; D011956:Receptors, Cell Surface; D043563:Receptors, Pheromone; C405956:gustatory receptor, Drosophila