Central and peripheral circadian oscillators in Drosophila

Area of Science:

• Chronobiology
• Molecular Biology
• Genetics

Background:

• Drosophila circadian rhythms are regulated by interlocked transcriptional-translational feedback loops.
• The Clock (Clk) and Period (per)/Timeless (tim) loops are key components of the core circadian oscillator.
• Tissue-specific variations in circadian clock mechanisms are increasingly recognized.

Purpose of the Study:

• To elucidate the negative feedback mechanism regulating Clock (Clk) gene expression in Drosophila.
• To investigate the role of Cryptochrome (CRY) in light-independent circadian rhythms, particularly in olfaction.
• To differentiate the roles of central and peripheral oscillators in regulating olfactory rhythms.

Main Methods:

• Analysis of transcriptional regulation within the Drosophila circadian clock.
• Investigating the function of the vrille (vri) gene in the Clk feedback loop.
• Studying the light-independent role of Cryptochrome (CRY) in olfactory rhythms.
• Comparing the function of peripheral (antennal) and central (lateral neuron) oscillators.

Main Results:

• Identified vrille (vri) as a transcriptional repressor of Clk, completing the Clk negative feedback loop and explaining opposite transcript cycling phases.
• Demonstrated a light-independent function for Cryptochrome (CRY) in the oscillator controlling olfaction rhythms.
• Olfactory rhythms depend on peripheral oscillators, with central lateral neuron oscillators having minimal impact.

Conclusions:

• The vrille gene is the negative component of the Clk feedback loop in Drosophila circadian clocks.
• Cryptochrome (CRY) has a conserved, light-independent role in circadian oscillator mechanisms, including olfaction.
• Peripheral oscillators, not central ones, are critical for Drosophila olfaction rhythms, differing from mammalian systems.