title: Drosophila hygrosensation requires the TRP channels water witch and nanchung.
abstract: The ability to detect variations in humidity is critical for many animals. Birds, reptiles and insects all show preferences for specific humidities that influence their mating, reproduction and geographic distribution. Because of their large surface area to volume ratio, insects are particularly sensitive to humidity, and its detection can influence their survival. Two types of hygroreceptors exist in insects: one responds to an increase (moist receptor) and the other to a reduction (dry receptor) in humidity. Although previous data indicated that mechanosensation might contribute to hygrosensation, the cellular basis of hygrosensation and the genes involved in detecting humidity remain unknown. To understand better the molecular bases of humidity sensing, we investigated several genes encoding channels associated with mechanosensation, thermosensing or water transport. Here we identify two Drosophila melanogaster transient receptor potential channels needed for sensing humidity: CG31284, named by us water witch (wtrw), which is required to detect moist air, and nanchung (nan), which is involved in detecting dry air. Neurons associated with specialized sensory hairs in the third segment of the antenna express these channels, and neurons expressing wtrw and nan project to central nervous system regions associated with mechanosensation. Construction of the hygrosensing system with opposing receptors may allow an organism to very sensitively detect changes in environmental humidity.
authors.affiliation: Department of Internal Medicine, Howard Hughes Medical Institute, Roy J. and Lucille A. Carver College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA.
authors.forename: Lei
authors.initials: L
authors.lastname: Liu
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Li
authors.forename: Runping
authors.initials: R
authors.lastname: Wang
authors.forename: Chong
authors.initials: C
authors.lastname: Yin
authors.forename: Qian
authors.initials: Q
authors.lastname: Dong
authors.forename: Huey
authors.initials: H
authors.lastname: Hing
authors.forename: Changsoo
authors.initials: C
authors.lastname: Kim
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Welsh
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D001522:Behavior, Animal / Q000502:physiology; D001692:Biological Transport; D002490:Central Nervous System / Q000166:cytology / Q000378:metabolism; D029721:Drosophila Proteins / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism*; D004594:Electrophysiology; D006813:Humidity; D009474:Neurons / Q000378:metabolism; D011401:Promoter Regions, Genetic / Q000235:genetics; D034622:RNA Interference; D013696:Temperature; D050051:Transient Receptor Potential Channels / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D014867:Water / Q000032:analysis* / Q000378:metabolism
chemical_list: D029721:Drosophila Proteins; C476010:Nan protein, Drosophila; D050051:Transient Receptor Potential Channels; C524730:wtrw protein, Drosophila; D014867:Water