Upstream open reading frames dynamically modulate CLOCK protein translation to regulate circadian rhythms and sleep

Area of Science:

• Molecular Biology
• Chronobiology
• Genetics

Background:

• Circadian rhythms are fundamental biological processes influenced by translational regulation.
• Upstream open reading frames (uORFs) are increasingly recognized as key modulators of gene expression.

Purpose of the Study:

• To investigate the role of uORFs in Drosophila circadian rhythm genes.
• To elucidate the function of uORFs in the core circadian clock gene Clock (Clk).

Main Methods:

• Analysis of uORF enrichment in Drosophila circadian genes.
• Experimental manipulation of Clk uORFs in Drosophila.
• Measurement of CLK protein levels and circadian cycle length.
• Assessment of clock gene expression rhythms and sleep patterns.

Main Results:

• uORFs are enriched in Drosophila circadian genes, with conserved uORFs in core clock genes.
• Clk uORFs rhythmically suppress CLK protein translation, especially during daylight.
• Deletion of Clk uORFs shortens the circadian cycle, alters gene expression rhythms, and increases morning sleep by reducing dopaminergic activity.
• Clk uORFs influence seasonal light adaptation and regulate numerous downstream genes.

Conclusions:

• uORFs are critical regulators of circadian clock gene expression and function in Drosophila.
• Clk uORFs provide a mechanism for fine-tuning circadian rhythms and adapting to environmental changes.
• This study highlights the significant impact of translational control via uORFs on circadian biology and physiology.