Abstract
Tobacco and Arabidopsis plants, expressing a transgene for the calcium-sensitive luminescent protein apoaequorin, revealed circadian oscillations in free cytosolic calcium that can be phase-shifted by light-dark signals. When apoaequorin was targeted to the chloroplast, circadian chloroplast calcium rhythms were likewise observed after transfer of the seedlings to constant darkness. Circadian oscillations in free calcium concentrations can be expected to control many calcium-dependent enzymes and processes accounting for circadian outputs. Regulation of calcium flux is therefore fundamental to the organization of circadian systems.
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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Aequorin / genetics
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Aequorin / metabolism
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Apoproteins / genetics
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Apoproteins / metabolism
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Arabidopsis / genetics
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Arabidopsis / metabolism*
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Calcium / metabolism*
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Calcium-Binding Proteins / genetics
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Calcium-Binding Proteins / metabolism
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Chloroplasts / metabolism*
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Circadian Rhythm*
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Cytosol / metabolism*
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Darkness
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Light
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Luminescence
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Nicotiana / genetics
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Nicotiana / metabolism*
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Plants, Genetically Modified
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Plants, Toxic*
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism
Substances
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Apoproteins
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Calcium-Binding Proteins
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Recombinant Proteins
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apoaequorin
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Aequorin
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Calcium