The PAS protein VIVID defines a clock-associated feedback loop that represses light input, modulates gating, and regulates clock resetting.
vvd, a gene regulating light responses in Neurospora, encodes a novel member of the PAS/LOV protein superfamily. VVD defines a circadian clock-associated autoregulatory feedback loop that influences light resetting, modulates circadian gating of input by connecting output and input, and regulates light adaptation. Rapidly light induced, vvd is an early repressor of light-regulated processes. Further, vvd is clock controlled; the clock gates light induction of vvd and the clock gene frq so identical signals yield greater induction in the morning. Mutation of vvd severely dampens gating, especially of frq, consistent with VVD modulating gating and phasing light-resetting responses. vvd null strains display distinct alterations in the phase-response curve to light. Thus VVD, although not part of the clock, contributes significantly to regulation within the Neurospora circadian system.
Department of Genetics, Dartmouth Medical School, Hanover, NH 03755, USA.
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Heintzen
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Loros
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Dunlap
D000595:Amino Acid Sequence; D015153:Blotting, Western; D002940:Circadian Rhythm; D003001:Cloning, Molecular; D003360:Cosmids / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics* / Q000502:physiology*; D008027:Light; D008954:Models, Biological; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D009154:Mutation; D009492:Neurospora crassa / Q000235:genetics* / Q000502:physiology*; D010641:Phenotype; D012313:RNA / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D013997:Time Factors
D005656:Fungal Proteins; D012333:RNA, Messenger; C423283:VVD protein, Neurospora crassa; D012313:RNA; D004247:DNA