Abstract
CRYPTOCHROME (CRY) is the primary circadian photoreceptor in Drosophila. We show that CRY binding to TIMELESS (TIM) is light-dependent in flies and irreversibly commits TIM to proteasomal degradation. In contrast, CRY degradation is dependent on continuous light exposure, indicating that the CRY-TIM interaction is transient. A novel cry mutation (cry(m)) reveals that CRY's photolyase homology domain is sufficient for light detection and phototransduction, whereas the carboxyl-terminal domain regulates CRY stability, CRY-TIM interaction, and circadian photosensitivity. This contrasts with the function of Arabidopsis CRY domains and demonstrates that insect and plant cryptochromes use different mechanisms.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Animals, Genetically Modified
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Cell Line
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Circadian Rhythm*
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Cryptochromes
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Cysteine Endopeptidases / metabolism
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Darkness
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Drosophila Proteins / chemistry*
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Drosophila Proteins / genetics
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Drosophila Proteins / metabolism*
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Drosophila melanogaster / genetics
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Drosophila melanogaster / physiology*
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Eye Proteins / chemistry*
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Eye Proteins / genetics
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Eye Proteins / metabolism*
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Female
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Light Signal Transduction
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Light*
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Male
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Multienzyme Complexes / metabolism
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Mutation
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Nuclear Proteins / metabolism
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Period Circadian Proteins
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Photoreceptor Cells, Invertebrate / chemistry*
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Photoreceptor Cells, Invertebrate / metabolism*
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Proteasome Endopeptidase Complex
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Protein Binding
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Protein Structure, Tertiary
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Receptors, G-Protein-Coupled
Substances
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Cryptochromes
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Drosophila Proteins
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Eye Proteins
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Multienzyme Complexes
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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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cry protein, Drosophila
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tim protein, Drosophila
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Cysteine Endopeptidases
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Proteasome Endopeptidase Complex