title: The dual-oscillator system of Drosophila melanogaster under natural-like temperature cycles.
abstract: Dual-oscillator systems that control morning and evening activities can be found in a wide range of animals. The two coupled oscillators track dawn and dusk and flexibly adapt their phase relationship to seasonal changes. This is also true for the fruit fly Drosophila melanogaster that serves as model organism to understand the molecular and anatomical bases of the dual-oscillator system. In the present study, the authors investigated which temperature parameters are crucial for timing morning and evening activity peaks by applying natural-like temperature cycles with different daylengths. The authors found that the morning peak synchronizes to the temperature increase in the morning and the evening peak to the temperature decrease in the afternoon. The two peaks did not occur at fixed absolute temperatures, but responded flexibly to daylength and overall temperature level. Especially, the phase of the evening peak clearly depended on the absolute temperature level: it was delayed at high temperatures, whereas the phase of the M peak was less influenced. This suggests that the two oscillators have different temperature sensitivities. The bimodal activity rhythm was absent in the circadian clock mutants Clk(Jrk) and cyc(01) and reduced in per(01) and tim(01) mutants. Whereas the activity of Clk(Jrk) mutants just followed the temperature cycles, that of per(01) and tim(01) mutants did not, suggesting that these mutants are not completely clockless. This study revealed new characteristics of the dual-oscillator system in Drosophila that were not detected under different photoperiods.
authors.affiliation: Neurobiology and Genetics, Theodor-Boveri Institute, Biocenter, University of Würzburg, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Bywalez
authors.forename: Pamela
authors.initials: P
authors.lastname: Menegazzi
authors.forename: Dirk
authors.initials: D
authors.lastname: Rieger
authors.forename: Benjamin
authors.initials: B
authors.lastname: Schmid
authors.forename: Charlotte
authors.initials: C
authors.lastname: Helfrich-Förster
authors.forename: Taishi
authors.initials: T
authors.lastname: Yoshii
mesh_terms: D056930:ARNTL Transcription Factors / Q000235:genetics / Q000378:metabolism; D000222:Adaptation, Physiological; D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks / Q000235:genetics; D056926:CLOCK Proteins / Q000235:genetics / Q000378:metabolism; D002940:Circadian Rhythm / Q000235:genetics; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D005838:Genotype; D008297:Male; D009043:Motor Activity; D009154:Mutation; D056950:Period Circadian Proteins / Q000235:genetics / Q000378:metabolism; D010641:Phenotype; D017440:Photoperiod; D013696:Temperature; D013697:Thermosensing; D013997:Time Factors
chemical_list: D056930:ARNTL Transcription Factors; C120526:Clk protein, Drosophila; D029721:Drosophila Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; C112805:cyc protein, Drosophila; C096445:tim protein, Drosophila; D056926:CLOCK Proteins