Comes a time

• Published in: Current opinion in plant biology Vol. 11; no. 5; pp. 514 - 520
• Main Author: McClung, C Robertson
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.10.2008; [Oxford, UK]: Pergamon: Elsevier Science
• Subjects: Arabidopsis - growth & development; Arabidopsis - metabolism; Arabidopsis - physiology; Arabidopsis thaliana; circadian rhythm; Circadian Rhythm - physiology; enzyme activity; Feedback, Physiological; gene expression; Gene Expression Profiling; gene expression regulation; Gene Expression Regulation, Plant; literature reviews; messenger RNA; metabolites; metabolome; Models, Biological; plant physiology; plants; post-translational modification; proteolysis; Signal Transduction; Systems Biology; transcription (genetics); transcriptome
• ISSN: 1369-5266; 1879-0356
• DOI: 10.1016/j.pbi.2008.06.010

The circadian clock is a selfsustaining oscillator with an endogenous period of ∼24 hours. The Arabidopsis clock is composed of a set of interlocking negative feedback loops entailing transcriptional, post-transcriptional, and post-translational, particularly regulated proteolysis, control. Clock control of the transcriptome is widespread; up to 90% of the transcriptome cycles in at least one condition in seedlings exposed to a variety of environmental cycles. Clock control extends to the metabolome, though diurnal oscillations in enzyme activities and metabolites are less dramatic than oscillations in cognate transcripts. Metabolites, including organic nitrogen intermediates, feed back to modulate clock function, consistent with the view of the circadian clock as a key integrator of metabolic signals to coordinate metabolism and physiology with the environment.