Circadian rhythms from multiple oscillators: lessons from diverse organisms.
The organization of biological activities into daily cycles is universal in organisms as diverse as cyanobacteria, fungi, algae, plants, flies, birds and man. Comparisons of circadian clocks in unicellular and multicellular organisms using molecular genetics and genomics have provided new insights into the mechanisms and complexity of clock systems. Whereas unicellular organisms require stand-alone clocks that can generate 24-hour rhythms for diverse processes, organisms with differentiated tissues can partition clock function to generate and coordinate different rhythms. In both cases, the temporal coordination of a multi-oscillator system is essential for producing robust circadian rhythms of gene expression and biological activity.
Bell-Pedersen
Deborah
D
Center for Research on Biological Clocks, Department of Biology, Texas A&M University, College Station, Texas 77843-3258, USA. dpedersen@mail.bio.tamu.edu
Cassone
Vincent M
VM
Earnest
David J
DJ
Golden
Susan S
SS
Hardin
Paul E
PE
Thomas
Terry L
TL
Zoran
Mark J
MJ
D000818:Animals; D001683:Biological Clocks / Q000502:physiology*; D002940:Circadian Rhythm / Q000502:physiology*; D056890:Eukaryota / Q000502:physiology*; D005658:Fungi / Q000502:physiology*; D006801:Humans; D008954:Models, Biological; D009492:Neurospora crassa