Adult-specific electrical silencing of pacemaker neurons uncouples molecular clock from circadian outputs.
BACKGROUND
Circadian rhythms regulate physiology and behavior through transcriptional feedback loops of clock genes running within specific pacemaker cells. In Drosophila, molecular oscillations in the small ventral lateral neurons (sLNvs) command rhythmic behavior under free-running conditions releasing the neuropeptide PIGMENT DISPERSING FACTOR (PDF) in a circadian fashion. Electrical activity in the sLNvs is also required for behavioral rhythmicity. Yet, how temporal information is transduced into behavior remains unclear.


RESULTS
Here we developed a new tool for temporal control of gene expression to obtain adult-restricted electrical silencing of the PDF circuit, which led to reversible behavioral arrhythmicity. Remarkably, PERIOD (PER) oscillations during the silenced phase remained unaltered, indicating that arrhythmicity is a direct consequence of the silenced activity. Accordingly, circadian axonal remodeling and PDF accumulation were severely affected during the silenced phase.


CONCLUSIONS
Although electrical activity of the sLNvs is not a clock component, it coordinates circuit outputs leading to rhythmic behavior.
Laboratorio de Genética del Comportamiento, Fundación Instituto Leloir and Instituto de Investigaciones Bioquímicas-Buenos Aires, Av. Patricias Argentinas 435, 1405-BWE Buenos Aires, Argentina.
Ana
A
Depetris-Chauvin
Jimena
J
Berni
Ezequiel J
EJ
Aranovich
Nara I
NI
Muraro
Esteban J
EJ
Beckwith
María Fernanda
MF
Ceriani
D000818:Animals; D030801:Animals, Genetically Modified / Q000235:genetics / Q000502:physiology; D001683:Biological Clocks; D001921:Brain / Q000196:embryology / Q000502:physiology; D002940:Circadian Rhythm; D004330:Drosophila / Q000235:genetics / Q000502:physiology*; D029721:Drosophila Proteins / Q000235:genetics / Q000502:physiology*; D004331:Drosophila melanogaster / Q000235:genetics / Q000502:physiology*; D020868:Gene Silencing; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D008564:Membrane Potentials; D009043:Motor Activity; D009474:Neurons / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000502:physiology*; D056950:Period Circadian Proteins / Q000235:genetics / Q000502:physiology*; D024661:Potassium Channels, Inwardly Rectifying / Q000235:genetics / Q000502:physiology*
D029721:Drosophila Proteins; C489461:Kir2.1 channel; D009479:Neuropeptides; C539040:PER protein, Drosophila; D056950:Period Circadian Proteins; D024661:Potassium Channels, Inwardly Rectifying; C485184:enhanced green fluorescent protein; C113883:pdf protein, Drosophila; D049452:Green Fluorescent Proteins