VRILLE Regulates Daily Neuropeptide Levels and Branching Patterns in Small Movement-Controlling Neurons to Drive Rhythmic Behavior in Fruit Flies

Inactivation of the vri gene abolishes activity rhythms in Drosophila despite maintaining circadian clock function.

• The circadian clock in Drosophila involves transcriptional feedback loops that regulate daily physiological and behavioral rhythms.
• The core loop is driven by CLOCK-CYCLE activators and PERIOD-TIMELESS repressors, with transcription peaking at dusk.
• An interlocked feedback loop utilizes PAR DOMAIN PROTEIN 1ε and VRILLE to regulate transcription peaking at dawn.
• Inactivation of vri disrupts multiple pathways important for activity rhythms, affecting PDF accumulation and neuron arborization.
• The findings indicate that vri is essential for maintaining activity rhythms, highlighting its role in clock output regulation.

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