Entrainment of Drosophila circadian rhythms by temperature cycles

The fruit fly, Drosophila melanogaster, has been a good organism for elucidating the molecular and cellular bases of circadian behavioral rhythms. The fly shows a bimodal locomotor rhythm with a period slightly different from 24-h. The rhythm synchronizes with the environmental cycle using light as a powerful zeitgeber. It is now believed that this rhythm is generated by two interlocked transcriptional feedback loops consisting of so-called clock genes. Light resets the clock loop through degradation of a clock protein, TIMELESS. Temperature is another powerful zeitgeber that can entrain the rhythm but the cellular and molecular basis for temperature entrainment is still under investigation. This review will try to give an overview of temperature entrainment, considering multiple clocks with different responsiveness to light and temperature.