Biological Clock and Genes Controlling Daily Rhythms in Fruit Flies

Most living organisms possess a circadian clock with a 24-hour period that helps them adapt to environmental conditions.

• Key clock genes such as period and timeless have been discovered in Drosophila.
• The molecular clock operates through negative feedback loops that create oscillations of clock gene mRNA.
• Post-translational modifications, including phosphorylations and ubiquitinations, influence protein stability and the timing of these oscillations.
• Clock cells function autonomously in both the brain and various peripheral tissues.
• Light synchronizes clock cells via cryptochrome in the brain and peripheral tissues, with additional involvement of eye photoreceptors.
• Different groups of neurons in the brain regulate sleep-wake rhythms, each with distinct roles influenced by environmental factors.

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