Resetting the Drosophila Clock by Photic Regulation of PER and a PER-TIM Complex

@article{Lee1996ResettingTD,
  title={Resetting the Drosophila Clock by Photic Regulation of PER and a PER-TIM Complex},
  author={C C Lee and Vaishali Parikh and T Itsukaichi and Kiho Bae and Isaac Edery},
  journal={Science},
  year={1996},
  volume={271},
  pages={1740 - 1744}
}
Circadian clocks can be reset by light stimulation. To investigate the mechanism of this phase shifting, the effects of light pulses on the protein and messenger RNA products of the Drosophila clock gene period (per) were measured. Photic stimuli perturbed the timing of the PER protein and messenger RNA cycles in a manner consistent with the direction and magnitude of the phase shift. In addition, the recently identified clock protein TIM (for timeless) interacted with PER in vivo, and this… 
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In the absence of PER or TIM, the levels of dCLOCK are constitutively low, indicating that PER and TIM also act as positive elements in the feedback loop by stimulating the production of dClOCK.
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TLDR
The cyclic expression of TIM protein in adult heads is shown and it lags behind peak levels of TIM RNA by several hours, suggesting that TIM mediates light-induced resetting of the circadian clock.
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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TLDR
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