A key body clock gene’s splicing controls seasonal changes through a winter-specific switch

The predominant isoform of the circadian clock gene in winter is regulated by photoperiod and temperature.

• Alternative splicing of the circadian gene influences seasonal responses of the neuropeptide Pigment Dispersing Factor (PDF).
• The canonical isoform of the gene is mainly sensitive to temperature, while the winter isoform responds to both temperature and light duration.
• The winter isoform helps maintain a 'winter lock' state in physiology and behavior by modulating PDF signaling.
• Behavioral and physiological differences were observed between flies with the alternative splicing and those with the canonical form.
• Flies with the alternative splicing did not fully mimic wild-type flies under winter conditions, indicating additional mechanisms for seasonal adaptation.

Simplified