Phosphorylation of period is influenced by cycling physical associations of double-time, period, and timeless in the Drosophila clock

Neuron. 2001 Jun;30(3):699-706. doi: 10.1016/s0896-6273(01)00320-8.


The clock gene double-time (dbt) encodes an ortholog of casein kinase Iepsilon that promotes phosphorylation and turnover of the PERIOD protein. Whereas the period (per), timeless (tim), and dClock (dClk) genes of Drosophila each contribute cycling mRNA and protein to a circadian clock, dbt RNA and DBT protein are constitutively expressed. Robust circadian changes in DBT subcellular localization are nevertheless observed in clock-containing cells of the fly head. These localization rhythms accompany formation of protein complexes that include PER, TIM, and DBT, and reflect periodic redistribution between the nucleus and the cytoplasm. Nuclear phosphorylation of PER is strongly enhanced when TIM is removed from PER/TIM/DBT complexes. The varying associations of PER, DBT and TIM appear to determine the onset and duration of nuclear PER function within the Drosophila clock.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Animals
  • Casein Kinase Iepsilon*
  • Cell Nucleus / metabolism
  • Circadian Rhythm / physiology*
  • Drosophila
  • Drosophila Proteins*
  • Insect Proteins / metabolism*
  • Nuclear Proteins / metabolism*
  • Period Circadian Proteins
  • Phosphorylation
  • Protein Kinases / metabolism*


  • Drosophila Proteins
  • Insect Proteins
  • Nuclear Proteins
  • PER protein, Drosophila
  • Period Circadian Proteins
  • dco protein, Drosophila
  • tim protein, Drosophila
  • Protein Kinases
  • Casein Kinase Iepsilon