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Updated: Jul 19, 2026

Rapid Analysis of Circadian Phenotypes in Arabidopsis Protoplasts Transfected with a Luminescent Clock Reporter
Published on: September 17, 2016
Light-dependent sequestration of TIMELESS by CRYPTOCHROME
M F Ceriani1, T K Darlington, D Staknis
1Department of Cell Biology and NSF Center for Biological Timing, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, CA 92037, USA.
Abstract:
Most organisms have circadian clocks consisting of negative feedback loops of gene regulation that facilitate adaptation to cycles of light and darkness. In this study, CRYPTOCHROME (CRY), a protein involved in circadian photoperception in Drosophila, is shown to block the function of PERIOD/TIMELESS (PER/TIM) heterodimeric complexes in a light-dependent fashion. TIM degradation does not occur under these conditions; thus, TIM degradation is uncoupled from abrogation of its function by light. CRY and TIM are part of the same complex and directly interact in yeast in a light-dependent fashion. PER/TIM and CRY influence the subcellular distribution of these protein complexes, which reside primarily in the nucleus after the perception of a light signal. Thus, CRY acts as a circadian photoreceptor by directly interacting with core components of the circadian clock.
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