Flies and fish: birds of a feather.
The identification of specific clock-containing structures has been a major endeavour of the circadian field for many years. This has lead to the identification of many key components of the circadian system, including the suprachiasmatic nucleus in mammals, and the eyes and pineal glands in lower vertebrates. However, the idea that these structures represent the only clocks in animals has been challenged by the discovery of peripheral pacemakers in most organs and tissues, and even a number of cell lines. In Drosophila, and vertebrates such as the zebrafish, these peripheral clocks appear to be highly autonomous, being set directly by the environmental light/dark cycle. However, a hierarchy of clocks may still exist in mammals. In this review, we examine some of the current views regarding peripheral clocks, their organization and how they are entrained.
Tamai
T Katherine
TK
University College London, Centre for Cell and Molecular Dynamics, Department of Anatomy and Developmental Biology, Rockefeller Building, 21 University Street, London WC1E 6JJ, UK.
Vardhanabhuti
V
V
Arthur
S
S
Foulkes
N S
NS
Whitmore
D
D
D000818:Animals; D030801:Animals, Genetically Modified; D001683:Biological Clocks / Q000235:genetics* / Q000528:radiation effects; D056926:CLOCK Proteins; D002460:Cell Line / Q000502:physiology / Q000528:radiation effects; D002478:Cells, Cultured / Q000502:physiology / Q000528:radiation effects; D002940:Circadian Rhythm / Q000235:genetics* / Q000528:radiation effects; D004330:Drosophila / Q000502:physiology*; D005786:Gene Expression Regulation / Q000502:physiology* / Q000528:radiation effects; D008027:Light; D008099:Liver / Q000502:physiology; D008322:Mammals / Q000502:physiology; D051379:Mice; D017440:Photoperiod; D051381:Rats; D013045:Species Specificity; D013493:Suprachiasmatic Nucleus / Q000502:physiology; D014018:Tissue Distribution / Q000235:genetics; D015534:Trans-Activators / Q000235:genetics; D015027:Zebrafish / Q000502:physiology*
D015534:Trans-Activators; D056926:CLOCK Proteins; C538944:Clock protein, mouse; C538945:Clock protein, rat