A mutant Drosophila homolog of mammalian Clock disrupts circadian rhythms and transcription of period and timeless

Cell. 1998 May 29;93(5):791-804. doi: 10.1016/s0092-8674(00)81440-3.


We report the identification, characterization, and cloning of a novel Drosophila circadian rhythm gene, dClock. The mutant, initially called Jrk, manifests dominant effects: heterozygous flies have a period alteration and half are arrhythmic, while homozygous flies are uniformly arrhythmic. Furthermore, these flies express low levels of the two clock proteins, PERIOD (PER) and TIMELESS (TIM), due to low per and tim transcription. Mapping and cloning of the Jrk gene indicates that it encodes the Drosophila homolog of mouse Clock. The mutant phenotype results from a premature stop codon that eliminates much of the putative activation domain of this bHLH-PAS transcription factor, thus explaining the dominant features of Jrk. The remarkable sequence conservation strongly supports common clock components present in the common ancestor of Drosophila and mammals.

Publication types

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

MeSH terms

  • Animals
  • Behavior, Animal
  • CLOCK Proteins
  • Chromosome Mapping
  • Circadian Rhythm / genetics*
  • Cloning, Molecular
  • Drosophila / genetics*
  • Drosophila Proteins*
  • Genes, Reporter
  • In Situ Hybridization
  • Insect Proteins / biosynthesis*
  • Insect Proteins / genetics
  • Mammals / genetics
  • Molecular Sequence Data
  • Mutagenesis
  • Mutation
  • Nuclear Proteins / biosynthesis*
  • Period Circadian Proteins
  • Trans-Activators / genetics*
  • Transcription, Genetic


  • Drosophila Proteins
  • Insect Proteins
  • Nuclear Proteins
  • PER protein, Drosophila
  • Period Circadian Proteins
  • Trans-Activators
  • tim protein, Drosophila
  • CLOCK Proteins
  • Clock protein, mouse

Associated data

  • GENBANK/AF065133