start-ver=1.4 cd-journal=joma no-vol=35 cd-vols= no-issue=15 article-no= start-page=6131 end-page=6141 dt-received= dt-revised= dt-accepted= dt-pub-year=2015 dt-pub=20150415 dt-online= en-article= kn-article= en-subject= kn-subject= en-title= kn-title=Cryptochrome-dependent and -independent circadian entrainment circuits in Drosophila. en-subtitle= kn-subtitle= en-abstract= kn-abstract= Entrainment to environmental light/dark (LD) cycles is a central function of circadian clocks. In Drosophila, entrainment is achieved by Cryptochrome (CRY) and input from the visual system. During activation by brief light pulses, CRY triggers the degradation of TIMELESS and subsequent shift in circadian phase. This is less important for LD entrainment, leading to questions regarding light input circuits and mechanisms from the visual system. Recent studies show that different subsets of brain pacemaker clock neurons, the morning (M) and evening (E) oscillators, have distinct functions in light entrainment. However, the role of CRY in M and E oscillators for entrainment to LD cycles is unknown. Here, we address this question by selectively expressing CRY in different subsets of clock neurons in a cry-null (cry0) mutant background. We were able to rescue the light entrainment deficits of cry0 mutants by expressing CRY in E oscillators but not in any other clock neurons. Par domain protein 1 molecular oscillations in the E, but not M, cells of cry0 mutants still responded to the LD phase delay. This residual light response was stemming from the visual system because it disappeared when all external photoreceptors were ablated genetically. We concluded that the E oscillators are the targets of light input via CRY and the visual system and are required for normal light entrainment. en-copyright= kn-copyright= en-aut-name=YoshiiTaishi en-aut-sei=Yoshii en-aut-mei=Taishi kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=1 ORCID= en-aut-name=Hermann-LuiblChristiane en-aut-sei=Hermann-Luibl en-aut-mei=Christiane kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=2 ORCID= en-aut-name=KistenpfennigChrista en-aut-sei=Kistenpfennig en-aut-mei=Christa kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=3 ORCID= en-aut-name=SchmidBenjamin en-aut-sei=Schmid en-aut-mei=Benjamin kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=4 ORCID= en-aut-name=TomiokaKenji en-aut-sei=Tomioka en-aut-mei=Kenji kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=5 ORCID= en-aut-name=Helfrich-FörsterCharlotte en-aut-sei=Helfrich-Förster en-aut-mei=Charlotte kn-aut-name= kn-aut-sei= kn-aut-mei= aut-affil-num=6 ORCID= affil-num=1 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=2 en-affil= kn-affil=Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg affil-num=3 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=4 en-affil= kn-affil=Max Planck Institute of Molecular Cell Biology and Genetics affil-num=5 en-affil= kn-affil=Graduate School of Natural Science and Technology, Okayama University affil-num=6 en-affil= kn-affil=2Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg en-keyword=circadian clock kn-keyword=circadian clock en-keyword=clock neurons kn-keyword=clock neurons en-keyword=Cryptochrome kn-keyword=Cryptochrome en-keyword=Drosophila melanogaster kn-keyword=Drosophila melanogaster en-keyword=light entrainment kn-keyword=light entrainment END