A large family of divergent Drosophila odorant-binding proteins expressed in gustatory and olfactory sensilla.
We identified a large family of putative odorant-binding protein (OBP) genes in the genome of Drosophila melanogaster. Some of these genes are present in large clusters in the genome. Most members are expressed in various taste organs, including gustatory sensilla in the labellum, the pharyngeal labral sense organ, dorsal and ventral cibarial organs, as well as taste bristles located on the wings and tarsi. Some of the gustatory OBPs are expressed exclusively in taste organs, but most are expressed in both olfactory and gustatory sensilla. Multiple binding proteins can be coexpressed in the same gustatory sensillum. Cells in the tarsi that express OBPs are required for normal chemosensation mediated through the leg, as ablation of these cells dramatically reduces the sensitivity of the proboscis extension reflex to sucrose. Finally, we show that OBP genes expressed in the pharyngeal taste sensilla are still expressed in the poxneuro genetic background while OBPs expressed in the labellum are not. These findings support a broad role for members of the OBP family in gustation and olfaction and suggest that poxneuro is required for cell fate determination of labellar but not pharyngeal taste organs.
Galindo
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Department of Pharmacology and Center for Basic Neuroscience, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9111, USA.
Smith
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D000595:Amino Acid Sequence; D000818:Animals; D030801:Animals, Genetically Modified; D019070:Cell Lineage; D004305:Dose-Response Relationship, Drug; D029721:Drosophila Proteins; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology*; D016678:Genome; D007763:Lac Operon; D008565:Membrane Proteins / Q000378:metabolism*; D008969:Molecular Sequence Data; D009154:Mutation; D009830:Olfactory Bulb / Q000196:embryology / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011956:Receptors, Cell Surface / Q000378:metabolism*; D018035:Receptors, Odorant / Q000096:biosynthesis* / Q000235:genetics*; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012903:Smell; D013395:Sucrose / Q000494:pharmacology; D013649:Taste; D013997:Time Factors; D014018:Tissue Distribution; D001616:beta-Galactosidase / Q000378:metabolism
D029721:Drosophila Proteins; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D018035:Receptors, Odorant; C405956:gustatory receptor, Drosophila; C045648:odorant-binding protein; D013395:Sucrose; D001616:beta-Galactosidase