title: H2O2-Sensitive Isoforms of Drosophila melanogaster TRPA1 Act in Bitter-Sensing Gustatory Neurons to Promote Avoidance of UV During Egg-Laying.
abstract: The evolutionarily conserved TRPA1 channel can sense various stimuli including temperatures and chemical irritants. Recent results have suggested that specific isoforms of Drosophila TRPA1 (dTRPA1) are UV-sensitive and that their UV sensitivity is due to H2O2sensitivity. However, whether such UV sensitivity served any physiological purposes in animal behavior was unclear. Here, we demonstrate that H2O2-sensitive dTRPA1 isoforms promote avoidance of UV when adult Drosophila females are selecting sites for egg-laying. First, we show that blind/visionless females are still capable of sensing and avoiding UV during egg-laying when intensity of UV is high yet within the range of natural sunlight. Second, we show that such vision-independent UV avoidance is mediated by a group of bitter-sensing neurons on the proboscis that express H2O2-sensitive dTRPA1 isoforms. We show that these bitter-sensing neurons exhibit dTRPA1-dependent UV sensitivity. Importantly, inhibiting activities of these bitter-sensing neurons, reducing their dTRPA1 expression, or reducing their H2O2-sensitivity all significantly reduced blind females' UV avoidance, whereas selectively restoring a H2O2-sensitive isoform of dTRPA1 in these neurons restored UV avoidance. Lastly, we show that specifically expressing the red-shifted channelrhodopsin CsChrimson in these bitter-sensing neurons promotes egg-laying avoidance of red light, an otherwise neutral cue for egg-laying females. Together, these results demonstrate a physiological role of the UV-sensitive dTRPA1 isoforms, reveal that adult Drosophila possess at least two sensory systems for detecting UV, and uncover an unexpected role of bitter-sensing taste neurons in UV sensing.
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Ananya R
authors.initials: AR
authors.lastname: Guntur
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Bin
authors.initials: B
authors.lastname: Gou
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655.
authors.forename: Pengyu
authors.initials: P
authors.lastname: Gu
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Ruo
authors.initials: R
authors.lastname: He
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Stern
authors.affiliation: Department of Neurobiology, University of Massachusetts Medical School, Worcester, Massachusetts 01655.
authors.forename: Yang
authors.initials: Y
authors.lastname: Xiang
authors.affiliation: Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710 yang@neuro.duke.edu.
authors.forename: Chung-Hui
authors.initials: CH
authors.lastname: Yang
mesh_terms: D000818:Animals; D002628:Chemoreceptor Cells / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D029721:Drosophila Proteins / Q000235:genetics* / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics* / Q000502:physiology; D005260:Female; D006861:Hydrogen Peroxide / Q000494:pharmacology; D007473:Ion Channels; D008124:Locomotion; D010058:Oviposition / Q000235:genetics* / Q000528:radiation effects; D020033:Protein Isoforms / Q000235:genetics / Q000378:metabolism; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels / Q000235:genetics* / Q000378:metabolism; D013649:Taste; D014466:Ultraviolet Rays
chemical_list: D029721:Drosophila Proteins; D007473:Ion Channels; D020033:Protein Isoforms; D000074025:TRPA1 Cation Channel; D050052:TRPC Cation Channels; C475684:TrpA1 protein, Drosophila; D006861:Hydrogen Peroxide
keywords: Drosophila egg-laying; UV-sensing; bitter-sensing neurons; dTRPA1