The PAS/LOV protein VIVID supports a rapidly dampened daytime oscillator that facilitates entrainment of the Neurospora circadian clock.

A light-entrainable circadian clock controls development and physiology in Neurospora crassa. Existing simple models for resetting based on light pulses (so-called nonparametric entrainment) predict that constant light should quickly send the clock to an arrhythmic state; however, such a clock would be of little use to an organism in changing photoperiods in the wild, and we confirm that true, albeit dampened, rhythmicity can be observed in extended light. This rhythmicity requires the PAS/LOV protein VIVID (VVD) that acts, in the light, to facilitate expression of an oscillator that is related to, but distinguishable from, the classic FREQUENCY/WHITE-COLLAR complex (FRQ/WCC)-based oscillator that runs in darkness. VVD prevents light resetting of the clock at dawn but, by influencing frq RNA turnover, promotes resetting at dusk, thereby allowing the clock to run through the dawn transition and take its phase cues from dusk. Consistent with this, loss of VVD yields a clock whose performance follows the simple predictions of earlier models, and overexpression of VVD restores rhythmicity in the light and sensitivity of phase to the duration of the photoperiod.

[1]  Yoshinobu Yamamoto,et al.  Role of Cyclic mPer2 Expression in the Mammalian Cellular Clock , 2005, Molecular and Cellular Biology.

[2]  D. Bell-Pedersen,et al.  Assignment of an essential role for the Neurospora frequency gene in circadian entrainment to temperature cycles. , 2005, Proceedings of the National Academy of Sciences of the United States of America.

[3]  Takao Kondo,et al.  No Transcription-Translation Feedback in Circadian Rhythm of KaiC Phosphorylation , 2005, Science.

[4]  Jay C Dunlap,et al.  The Neurospora Circadian System , 2004, Journal of biological rhythms.

[5]  M. Merrow,et al.  Photoperiodism in Neurospora Crassa , 2004, Journal of biological rhythms.

[6]  G. Coupland,et al.  Induction of flowering by seasonal changes in photoperiod , 2004, The EMBO journal.

[7]  M. Merrow,et al.  Entrainment Dissociates Transcription and Translation of a Circadian Clock Gene in Neurospora , 2004, Current Biology.

[8]  S. Golden.  Timekeeping in bacteria: the cyanobacterial circadian clock. , 2003, Current opinion in microbiology.

[9]  S. Kay,et al.  FKF1 is essential for photoperiodic-specific light signalling in Arabidopsis , 2003, Nature.

[10]  Alejandro Correa,et al.  Multiple oscillators regulate circadian gene expression in Neurospora , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[11]  C. Schwerdtfeger,et al.  VIVID is a flavoprotein and serves as a fungal blue light photoreceptor for photoadaptation , 2003, The EMBO journal.

[12]  S. Brody,et al.  Circadian Rhythms in Neurospora Crassa: Farnesol or Geraniol Allow Expression of Rhythmicity in the Otherwise Arrhythmic Strains frq 10, wc-1, and wc-2 , 2003, Journal of biological rhythms.

[13]  S. Daan,et al.  The Art of Entrainment , 2003, Journal of biological rhythms.

[14]  A. Sehgal,et al.  A Fly's Eye View of Circadian Entrainment , 2003, Journal of biological rhythms.

[15]  Yi Liu,et al.  Functional conservation of light, oxygen, or voltage domains in light sensing , 2003, Proceedings of the National Academy of Sciences of the United States of America.

[16]  S. Kay,et al.  Living by the calendar: how plants know when to flower , 2003, Nature Reviews Molecular Cell Biology.

[17]  J. Christie,et al.  Phototropin LOV domains exhibit distinct roles in regulating photoreceptor function. , 2002, The Plant journal : for cell and molecular biology.

[18]  Michael F. Covington,et al.  ELF3 Modulates Resetting of the Circadian Clock in Arabidopsis , 2001, The Plant Cell Online.

[19]  D. R. Wagner,et al.  EARLY FLOWERING3 Encodes a Novel Protein That Regulates Circadian Clock Function and Flowering in Arabidopsis , 2001, The Plant Cell Online.

[20]  J. Dunlap,et al.  Circadian Clock-Specific Roles for the Light Response Protein WHITE COLLAR-2 , 2001, Molecular and Cellular Biology.

[21]  D. Bell-Pedersen,et al.  vvd is required for light adaptation of conidiation-specific genes of Neurospora crassa, but not circadian conidiation. , 2001, Fungal genetics and biology : FG & B.

[22]  P. Ruoff,et al.  The Goodwin model: simulating the effect of light pulses on the circadian sporulation rhythm of Neurospora crassa. , 2001, Journal of theoretical biology.

[23]  J. Dunlap,et al.  The PAS Protein VIVID Defines a Clock-Associated Feedback Loop that Represses Light Input, Modulates Gating, and Regulates Clock Resetting , 2001, Cell.

[24]  C. Schwerdtfeger,et al.  Blue light adaptation and desensitization of light signal transduction in Neurospora crassa , 2001, Molecular microbiology.

[25]  Anthony Hall,et al.  The ELF3 zeitnehmer regulates light signalling to the circadian clock , 2000, Nature.

[26]  M. Hastings,et al.  Circadian clockwork: two loops are better than one , 2000, Nature Reviews Neuroscience.

[27]  Paolo Sassone-Corsi,et al.  Multilevel regulation of the circadian clock , 2000, Nature Reviews Molecular Cell Biology.

[28]  P. Lakin-Thomas,et al.  Circadian rhythms in Neurospora crassa: lipid deficiencies restore robust rhythmicity to null frequency and white-collar mutants. , 2000, Proceedings of the National Academy of Sciences of the United States of America.

[29]  G. Macino,et al.  Role of a white collar‐1–white collar‐2 complex in blue‐light signal transduction , 1999, The EMBO journal.

[30]  J. Dunlap.  Molecular Bases for Circadian Clocks , 1999, Cell.

[31]  Lily Yan,et al.  Light-Induced Resetting of a Mammalian Circadian Clock Is Associated with Rapid Induction of the mPer1 Transcript , 1997, Cell.

[32]  H. Nakashima,et al.  Effects of light-dark cycles on the circadian conidiation rhythm inNeurospora crassa , 1997, Journal of Plant Research.

[33]  E. Selker,et al.  Improved plasmids for gene targeting at the his-3 locus of Neurospora crassa by electroporation , 1997 .

[34]  Yi Liu,et al.  Alternative Initiation of Translation and Time-Specific Phosphorylation Yield Multiple Forms of the Essential Clock Protein FREQUENCY , 1997, Cell.

[35]  M. Merrow,et al.  Dissection of a circadian oscillation into discrete domains. , 1997, Proceedings of the National Academy of Sciences of the United States of America.

[36]  Jennifer J. Loros,et al.  Light-induced resetting of a circadian clock is mediated by a rapid increase in frequency transcript , 1995, Cell.

[37]  J. Dunlap,et al.  Circadian clock locus frequency: protein encoded by a single open reading frame defines period length and temperature compensation. , 1994, Proceedings of the National Academy of Sciences of the United States of America.

[38]  J. Dunlap,et al.  Negative feedback defining a circadian clock: autoregulation of the clock gene frequency. , 1994, Science.

[39]  V. Gooch,et al.  Temperature Effects on the Resetting of the Phase of the Neurospora Circadian Rhythm , 1994, Journal of biological rhythms.

[40]  J. Loros,et al.  Loss of Temperature Compensation of Circadian Period Length in the frq-9 Mutant of Neurospora crassa , 1986, Journal of biological rhythms.

[41]  M. Case,et al.  Cis-acting and trans-acting regulatory mutations define two types of promoters controlled by the qa-1F gene of Neurospora , 1984, Cell.

[42]  E L Peterson,et al.  A limit cycle interpretation of a mosquito circadian oscillator. , 1980, Journal of theoretical biology.

[43]  R Satter,et al.  Effects of Light-Dark Cycles , 1976, Science.

[44]  T Roenneberg,et al.  Automated recordings of bioluminescence with special reference to the analysis of circadian rhythms. , 2000, Methods in enzymology.

[45]  C. Pittendrigh.  Circadian Systems: Entrainment , 1981 .