Molecular components of the circadian system in Drosophila

Annu Rev Physiol. 2001;63:729-55. doi: 10.1146/annurev.physiol.63.1.729.


Much of our current understanding of how circadian rhythms are generated is based on work done with Drosophila melanogaster. Molecular mechanisms used to assemble an endogenous clock in this organism are now known to underlie circadian rhythms in many other species, including mammals. The genetic amenability of Drosophila has led to the identification of some genes that encode components of the clock (so-called clock genes) and others that either link the clock to the environment or act downstream of it. The clock provides time-of-day cues by regulating levels of specific gene products such that they oscillate with a circadian rhythm. The mechanisms that synchronize these oscillations to light are understood to some extent. However, there are still large gaps in our knowledge, in particular with respect to the mechanisms used by the clock to control overt rhythms. It has, however, become clear that in addition to the brain clock, autonomous or semi-autonomous clocks occur in peripheral tissues where they confer circadian regulation on specific functions.

Publication types

  • Review

MeSH terms

  • Animals
  • CLOCK Proteins
  • Circadian Rhythm / genetics*
  • Drosophila Proteins*
  • Drosophila melanogaster / physiology*
  • Gene Expression / physiology
  • Insect Proteins / genetics
  • Insect Proteins / metabolism
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism
  • Period Circadian Proteins
  • Transcription Factors / genetics
  • Transcription Factors / metabolism


  • Clk protein, Drosophila
  • Drosophila Proteins
  • Insect Proteins
  • Nuclear Proteins
  • PER protein, Drosophila
  • Period Circadian Proteins
  • Transcription Factors
  • tim protein, Drosophila
  • CLOCK Proteins