Morning and evening peaks of activity rely on different clock neurons of the Drosophila brain.
In Drosophila, a 'clock' situated in the brain controls circadian rhythms of locomotor activity. This clock relies on several groups of neurons that express the Period (PER) protein, including the ventral lateral neurons (LN(v)s), which express the Pigment-dispersing factor (PDF) neuropeptide, and the PDF-negative dorsal lateral neurons (LN(d)s). In normal cycles of day and night, adult flies exhibit morning and evening peaks of activity; however, the contribution of the different clock neurons to the rest-activity pattern remains unknown. Here, we have used targeted expression of PER to restore the clock function of specific subsets of lateral neurons in arrhythmic per(0) mutant flies. We show that PER expression restricted to the LN(v)s only restores the morning activity, whereas expression of PER in both the LN(v)s and LN(d)s also restores the evening activity. This provides the first neuronal bases for 'morning' and 'evening' oscillators in the Drosophila brain. Furthermore, we show that the LN(v)s alone can generate 24 h activity rhythms in constant darkness, indicating that the morning oscillator is sufficient to drive the circadian system.
Institut de Neurobiologie Alfred Fessard (NGI, CNRS UPR 2216), Centre National de la Recherche Scientifique, av. de la terrasse, 91198 Gif-sur-Yvette, France.
Brigitte
B
Grima
Elisabeth
E
Chélot
Ruohan
R
Xia
François
F
Rouyer
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology / Q000528:radiation effects; D001683:Biological Clocks / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D001921:Brain / Q000166:cytology* / Q000502:physiology* / Q000528:radiation effects; D002940:Circadian Rhythm / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D003624:Darkness; D029721:Drosophila Proteins / Q000235:genetics / Q000378:metabolism; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D015870:Gene Expression; D008027:Light; D009043:Motor Activity / Q000235:genetics / Q000502:physiology* / Q000528:radiation effects; D009474:Neurons / Q000502:physiology* / Q000528:radiation effects; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D056950:Period Circadian Proteins
D029721:Drosophila Proteins; D009479:Neuropeptides; D009687:Nuclear Proteins; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; C113883:pdf protein, Drosophila