title: Drosophila Ionotropic Receptor 25a mediates circadian clock resetting by temperature.
abstract: Circadian clocks are endogenous timers adjusting behaviour and physiology with the solar day. Synchronized circadian clocks improve fitness and are crucial for our physical and mental well-being. Visual and non-visual photoreceptors are responsible for synchronizing circadian clocks to light, but clock-resetting is also achieved by alternating day and night temperatures with only 2-4 °C difference. This temperature sensitivity is remarkable considering that the circadian clock period (~24 h) is largely independent of surrounding ambient temperatures. Here we show that Drosophila Ionotropic Receptor 25a (IR25a) is required for behavioural synchronization to low-amplitude temperature cycles. This channel is expressed in sensory neurons of internal stretch receptors previously implicated in temperature synchronization of the circadian clock. IR25a is required for temperature-synchronized clock protein oscillations in subsets of central clock neurons. Extracellular leg nerve recordings reveal temperature- and IR25a-dependent sensory responses, and IR25a misexpression confers temperature-dependent firing of heterologous neurons. We propose that IR25a is part of an input pathway to the circadian clock that detects small temperature differences. This pathway operates in the absence of known 'hot' and 'cold' sensors in the Drosophila antenna, revealing the existence of novel periphery-to-brain temperature signalling channels.
authors.affiliation: Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK.
authors.forename: Chenghao
authors.initials: C
authors.lastname: Chen
authors.affiliation: School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, UK.
authors.forename: Edgar
authors.initials: E
authors.lastname: Buhl
authors.affiliation: Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK.
authors.forename: Min
authors.initials: M
authors.lastname: Xu
authors.affiliation: Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Vincent
authors.initials: V
authors.lastname: Croset
authors.affiliation: Cambridge Centre for Proteomics, Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Johanna S
authors.initials: JS
authors.lastname: Rees
authors.affiliation: Cambridge Centre for Proteomics, Department of Biochemistry and Cambridge Systems Biology Centre, University of Cambridge, Tennis Court Road, Cambridge CB2 1QW, UK.
authors.forename: Kathryn S
authors.initials: KS
authors.lastname: Lilley
authors.affiliation: Center for Integrative Genomics, Faculty of Biology and Medicine, University of Lausanne, CH-1015 Lausanne, Switzerland.
authors.forename: Richard
authors.initials: R
authors.lastname: Benton
authors.affiliation: School of Physiology and Pharmacology, University of Bristol, University Walk, Bristol BS8 1TD, UK.
authors.forename: James J L
authors.initials: JJ
authors.lastname: Hodge
authors.affiliation: Department of Cell and Developmental Biology, University College London, 21 University Street, London WC1E 6DE, UK.
authors.forename: Ralf
authors.initials: R
authors.lastname: Stanewsky
mesh_terms: D000818:Animals; D056926:CLOCK Proteins / Q000378:metabolism; D057906:Circadian Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism*; D004331:Drosophila melanogaster / Q000166:cytology / Q000502:physiology*; D005121:Extremities / Q000294:innervation; D005260:Female; D008297:Male; D008465:Mechanoreceptors / Q000166:cytology / Q000378:metabolism; D058468:Receptors, Ionotropic Glutamate / Q000235:genetics / Q000378:metabolism*; D011984:Sensory Receptor Cells / Q000378:metabolism; D013696:Temperature
chemical_list: D029721:Drosophila Proteins; D058468:Receptors, Ionotropic Glutamate; C555767:ionotropic receptor 25a, Drosophila; D056926:CLOCK Proteins