Evidence that the TIM light response is relevant to light-induced phase shifts in Drosophila melanogaster

Neuron. 1998 Jul;21(1):225-34. doi: 10.1016/s0896-6273(00)80529-2.


Light is a major environmental signal for the entrainment of circadian rhythms. In Drosophila melanogaster, recent experiments suggest that photic information is transduced to the clock through the timeless gene product, TIM. We provide genetic and spectral evidence supporting the relevance of TIM light responses to clock resetting. A missense mutant TIM, TIM-SL, exhibits greater sensitivity to light in both TIM protein disappearance and locomotor activity phase shifting assays. We show that the wavelength dependence of light-induced decreases in TIM levels and that of light-mediated phase shifting are virtually identical. Analysis of dose response of TIM disappearance in a variety of mutant genotypes suggests cell-autonomous light responses that are largely independent of the canonical visual transduction pathway.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Behavior, Animal / physiology
  • Brain / cytology
  • Brain / physiology
  • Circadian Rhythm / physiology*
  • Drosophila Proteins*
  • Drosophila melanogaster / genetics
  • Drosophila melanogaster / physiology*
  • Eye / metabolism
  • Insect Proteins / genetics
  • Insect Proteins / radiation effects*
  • Light Signal Transduction / physiology
  • Light*
  • Motor Activity / physiology
  • Motor Activity / radiation effects
  • Mutation / physiology
  • Neurons / physiology
  • Species Specificity


  • Drosophila Proteins
  • Insect Proteins
  • tim protein, Drosophila