PMID:9727980

Citation	Ishiura, M, Kutsuna, S, Aoki, S, Iwasaki, H, Andersson, CR, Tanabe, A, Golden, SS, Johnson, CH and Kondo, T (1998) Expression of a gene cluster kaiABC as a circadian feedback process in cyanobacteria. Science 281:1519-23
Abstract	Cyanobacteria are the simplest organisms known to have a circadian clock. A circadian clock gene cluster kaiABC was cloned from the cyanobacterium Synechococcus. Nineteen clock mutations were mapped to the three kai genes. Promoter activities upstream of the kaiA and kaiB genes showed circadian rhythms of expression, and both kaiA and kaiBC messenger RNAs displayed circadian cycling. Inactivation of any single kai gene abolished these rhythms and reduced kaiBC-promoter activity. Continuous kaiC overexpression repressed the kaiBC promoter, whereas kaiA overexpression enhanced it. Temporal kaiC overexpression reset the phase of the rhythms. Thus, a negative feedback control of kaiC expression by KaiC generates a circadian oscillation in cyanobacteria, and KaiA sustains the oscillation by enhancing kaiC expression.
Links	PubMed
Keywords	Amino Acid Sequence; Bacterial Proteins/genetics; Biological Clocks/genetics; Circadian Rhythm/genetics; Circadian Rhythm Signaling Peptides and Proteins; Cloning, Molecular; Cyanobacteria/genetics; Cyanobacteria/physiology; Feedback; Gene Expression Regulation, Bacterial; Genes, Bacterial; Genes, Reporter; Luminescence; Models, Biological; Molecular Sequence Data; Multigene Family; Mutation; Promoter Regions, Genetic; Recombinant Fusion Proteins; Transcription, Genetic
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Annotations

Gene product	Qualifier	GO Term	Evidence Code	with/from	Aspect	Extension	Notes	Status
SYNE7:KAIC		GO:0042754: negative regulation of circadian rhythm	ECO:0000315:		P		Figure 2, Figure 4F	complete CACAO 2595
SYNE7:KAIC	involved_in	GO:0042754: negative regulation of circadian rhythm	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
SYNE7:KAIA		GO:0035308 : negative regulation of protein dephosphorylation	ECO:0000315:		P		Figure 3B, 3C	complete CACAO 2593
SYNE7:KAIA	involved_in	GO:0035308: negative regulation of protein dephosphorylation	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete
SYNE7:KAIB		GO:0042752: regulation of circadian rhythm	ECO:0000315:		P		Figure 2E	complete CACAO 2594
SYNE7:KAIB	involved_in	GO:0042752: regulation of circadian rhythm	ECO:0000315: mutant phenotype evidence used in manual assertion		P		Seeded From UniProt	complete

References

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