Functional identification of the mouse circadian Clock gene by transgenic BAC rescue

Cell. 1997 May 16;89(4):655-67. doi: 10.1016/s0092-8674(00)80246-9.


As a complementary approach to positional cloning, we used in vivo complementation with bacterial artificial chromosome (BAC) clones expressed in transgenic mice to identify the circadian Clock gene. A 140 kb BAC transgene completely rescued both the long period and the loss-of-rhythm phenotypes in Clock mutant mice. Analysis with overlapping BAC transgenes demonstrates that a large transcription unit spanning approximately 100,000 base pairs is the Clock gene and encodes a novel basic-helix-loop-helix-PAS domain protein. Overexpression of the Clock transgene can shorten period length beyond the wild-type range, which provides additional evidence that Clock is an integral component of the circadian pacemaking system. Taken together, these results provide a proof of principle that "cloning by rescue" is an efficient and definitive method in mice.

Publication types

  • 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
  • Base Sequence
  • CLOCK Proteins
  • Chromosome Mapping
  • Chromosomes, Bacterial
  • Circadian Rhythm / genetics*
  • Circadian Rhythm / physiology
  • Cloning, Molecular
  • DNA Primers / genetics
  • Female
  • Genetic Complementation Test
  • In Situ Hybridization
  • Male
  • Mice
  • Mice, Transgenic
  • Mutation
  • Phenotype
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Trans-Activators / genetics*
  • Trans-Activators / physiology


  • DNA Primers
  • RNA, Messenger
  • Trans-Activators
  • CLOCK Proteins
  • Clock protein, mouse

Associated data

  • GENBANK/AF000998