A Tug-of-War between Cryptochrome and the Visual System Allows the Adaptation of Evening Activity to Long Photoperiods in Drosophila melanogaster

In many animals, the circadian clock plays a role in adapting to the coming season by measuring day length. The mechanism for measuring day length and its neuronal circuits remains elusive, however. Under laboratory conditions, the fruit fly, Drosophila melanogaster, displays 2 activity peaks: one i...

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Bibliographic Details
Published in:Journal of biological rhythms 2018-02, Vol.33 (1), p.24-34
Main Authors: Kistenpfennig, Christa, Nakayama, Mayumi, Nihara, Ruri, Tomioka, Kenji, Helfrich-Förster, Charlotte, Yoshii, Taishi
Format: Article
Language:English
Subjects:
Adaptation
Adaptation, Physiological - physiology
Animals
Brain
Circadian Clocks - physiology
Circadian rhythm
Circadian Rhythm - physiology
Circadian rhythms
Cryptochromes - metabolism
Drosophila melanogaster
Drosophila melanogaster - metabolism
Drosophila melanogaster - physiology
Drosophila Proteins - metabolism
Evening
Eye (anatomy)
Eye Proteins - metabolism
Eyelets
Insects
Light
Morning
Motor Activity - physiology
Neurons
Neurons - physiology
Ocelli
Oscillators
Period Circadian Proteins - metabolism
Photoperiod
Photoperiods
Photoreception
Photoreceptors
Signaling
Tracking
Visual effects
Visual pathways
Visual signals
Visual system
War
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Summary:In many animals, the circadian clock plays a role in adapting to the coming season by measuring day length. The mechanism for measuring day length and its neuronal circuits remains elusive, however. Under laboratory conditions, the fruit fly, Drosophila melanogaster, displays 2 activity peaks: one in the morning and one in the evening. These peaks appear to be regulated by 2 separate circadian oscillators (the morning and evening oscillators) that reside in different subsets of pacemaker clock neurons in the brain. The morning and evening activity peaks can flexibly change their phases to adapt to different photoperiods by tracking dawn and dusk, respectively. In this study, we found that cryptochrome (CRY) in the evening oscillators (the fifth small ventral lateral neuron [5th s-LNv] and the dorsal lateral neurons [LNds]) limits the ability of the evening peak to track dusk during long days. In contrast, light signaling from the external photoreceptors (compound eyes, ocelli, and Hofbauer–Buchner eyelets) increases the ability of the evening peak to track dusk. At the molecular level, CRY signaling dampens the amplitude of PAR-domain protein 1 (PDP1) oscillations in most clock neurons during long days, whereas signaling from the visual system increases these amplitudes. Thus, our results suggest that light inputs from the two major circadian photoreceptors, CRY and the visual system, have opposite effects on day length adaptation. Their tug-of-war appears to determine the precise phase adjustment of evening activity.
ISSN:0748-7304
1552-4531
DOI:10.1177/0748730417738612