A hormone-sensitive receptor controls daily rhythms in fruit flies

Overexpression or knockdown of the nuclear receptor E75 disrupts rest:activity rhythms in Drosophila melanogaster.

• E75 is associated with circadian functions and was identified through a gain-of-function screen.
• Manipulating E75 levels in clock neurons dampens molecular oscillations related to circadian rhythms.
• E75 represses the gene for the transcriptional activator CLOCK (CLK), potentially affecting circadian output.
• PER may inhibit E75's activity on the Clk promoter, suggesting a regulatory mechanism in circadian transcription.
• The ecdysone receptor, expressed in central clock cells, produces effects on circadian rhythms similar to E75.
• E75 appears to help maintain circadian rhythms during stressful conditions, indicating a role for steroid signalling.

Simplified