Circadian changes in Drosophila motor terminals

Area of Science:

• Neuroscience
• Chronobiology
• Molecular Biology

Background:

• Circadian clocks regulate daily rhythms in behavior and physiology.
• The fruit fly Drosophila melanogaster is a model organism for studying circadian rhythms.
• Neuromuscular junctions are critical for motor control and their plasticity is essential for function.

Purpose of the Study:

• To investigate the impact of the circadian clock on the morphology of Drosophila neuromuscular terminals.
• To determine if circadian rhythms in neuromuscular structure persist under constant conditions and are affected by aging.
• To examine the role of core clock genes (timeless and period) in regulating neuromuscular morphology.

Main Methods:

• Morphological analysis of Drosophila flight neuromuscular terminals.
• Assessment of synaptic bouton size rhythmicity under light/dark cycles and constant darkness.
• Evaluation of morphological changes in aged flies and clock mutants (timeless and period).

Main Results:

• Drosophila flight neuromuscular terminals exhibit daily morphological changes, including rhythmic synaptic bouton size.
• This rhythm persists in constant darkness but is lost with aging.
• Mutations in timeless (tim) and period (per) disrupt this rhythm and affect neuronal branching patterns.

Conclusions:

• The circadian clock influences neuromuscular junction morphology in Drosophila.
• Clock gene mutations have pleiotropic effects, impacting both rhythmic and nonrhythmic neuronal structures.
• These findings highlight novel roles for circadian clock genes beyond behavioral rhythms.