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.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, Non-P.H.S.
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Biological Clocks*
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Cell Line
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Cell Nucleus / metabolism
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Circadian Rhythm*
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Cryptochromes
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Cytoplasm / metabolism
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Darkness
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Dimerization
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Drosophila
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Drosophila Proteins*
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Eye Proteins*
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Flavoproteins / genetics
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Flavoproteins / metabolism*
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Green Fluorescent Proteins
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Insect Proteins / genetics
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Insect Proteins / metabolism*
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Light*
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Luminescent Proteins
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Mutation
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Period Circadian Proteins
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Photoreceptor Cells, Invertebrate*
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Receptors, G-Protein-Coupled
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Recombinant Fusion Proteins / metabolism
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Transfection
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Yeasts / genetics
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Yeasts / metabolism
Substances
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Cryptochromes
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Drosophila Proteins
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Eye Proteins
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Flavoproteins
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Insect Proteins
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Luminescent Proteins
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Nuclear Proteins
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PER protein, Drosophila
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Period Circadian Proteins
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Receptors, G-Protein-Coupled
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Recombinant Fusion Proteins
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cry protein, Drosophila
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tim protein, Drosophila
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Green Fluorescent Proteins