title: PDF neuron firing phase-shifts key circadian activity neurons in Drosophila.
abstract: Our experiments address two long-standing models for the function of the Drosophila brain circadian network: a dual oscillator model, which emphasizes the primacy of PDF-containing neurons, and a cell-autonomous model for circadian phase adjustment. We identify five different circadian (E) neurons that are a major source of rhythmicity and locomotor activity. Brief firing of PDF cells at different times of day generates a phase response curve (PRC), which mimics a light-mediated PRC and requires PDF receptor expression in the five E neurons. Firing also resembles light by causing TIM degradation in downstream neurons. Unlike light however, firing-mediated phase-shifting is CRY-independent and exploits the E3 ligase component CUL-3 in the early night to degrade TIM. Our results suggest that PDF neurons integrate light information and then modulate the phase of E cell oscillations and behavioral rhythms. The results also explain how fly brain rhythms persist in constant darkness and without CRY.
authors.affiliation: Department of Biology, Brandeis University, Waltham, United States.
authors.forename: Fang
authors.initials: F
authors.lastname: Guo
authors.affiliation: Howard Hughes Medical Institute, Brandeis University, Waltham, United States.
authors.forename: Isadora
authors.initials: I
authors.lastname: Cerullo
authors.affiliation: Department of Biology, Brandeis University, Waltham, United States.
authors.forename: Xiao
authors.initials: X
authors.lastname: Chen
authors.affiliation: Department of Biology, Brandeis University, Waltham, United States.
authors.forename: Michael
authors.initials: M
authors.lastname: Rosbash
mesh_terms: D000818:Animals; D001522:Behavior, Animal; D001683:Biological Clocks / Q000502:physiology; D002940:Circadian Rhythm; D003593:Cytoplasm / Q000378:metabolism; D004331:Drosophila melanogaster / Q000502:physiology*; D005786:Gene Expression Regulation; D005838:Genotype; D007150:Immunohistochemistry; D008027:Light; D008124:Locomotion; D008297:Male; D009046:Motor Neurons / Q000502:physiology*; D009991:Oscillometry; D034622:RNA Interference; D015398:Signal Transduction
keywords: D. melanogaster; PDF; circadian rhythms; locomotor activity; neuron activity; neuroscience; phase shift