Publication Date:
1998-09-04
Description:
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.〈br /〉〈span class="detail_caption"〉Notes: 〈/span〉Ishiura, M -- Kutsuna, S -- Aoki, S -- Iwasaki, H -- Andersson, C R -- Tanabe, A -- Golden, S S -- Johnson, C H -- Kondo, T -- MH01179/MH/NIMH NIH HHS/ -- New York, N.Y. -- Science. 1998 Sep 4;281(5382):1519-23.〈br /〉〈span class="detail_caption"〉Author address: 〈/span〉Division of Biological Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, 464-8602, Japan. ishiura@bio.nagoya-u.ac.jp〈br /〉〈span class="detail_caption"〉Record origin:〈/span〉 〈a href="http://www.ncbi.nlm.nih.gov/pubmed/9727980" target="_blank"〉PubMed〈/a〉
Keywords:
Amino Acid Sequence
;
Bacterial Proteins/*genetics
;
Biological Clocks/*genetics
;
Circadian Rhythm/*genetics
;
Circadian Rhythm Signaling Peptides and Proteins
;
Cloning, Molecular
;
Cyanobacteria/*genetics/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
Print ISSN:
0036-8075
Electronic ISSN:
1095-9203
Topics:
Biology
,
Chemistry and Pharmacology
,
Computer Science
,
Medicine
,
Natural Sciences in General
,
Physics
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