A minimal circadian clock model


The coordination of biological activities into daily cycles provides an important advantage for the fitness of diverse organisms. Thereby, an internal circadian oscillator drives gene expression in an approximate 24 hours rhythm. Circadian clocks are found in most eukaryotes. In prokaryotes only cyanobacteria are known to regulate their activities in a circadian rhythm. In vitro experiments showed that three cyanobacterial proteins KaiA, KaiB and KaiC together with ATP are sufficient to generate temperature-compensated circadian oscillations of KaiC protein phosphorylation. Thus, in contrast to eukaryotic clock models the cyanobacterial core oscillator operates independently of transcription and translation processes. Most previous models of the bacterial circadian clock used complex mathematical descriptions. Here, we suggest a minimal and manageable heuristic system. Even though only four reaction steps were assumed, our model exhibited sustained oscillations of KaiC phosphorylation. A simulation of known experimental data was successful as well as oscillations maintained even for a concerted increase of Kai protein concentration. Thus, we provided a useful minimal system of differential equations which might serve as a core module of the holistic cyanobacterial clockwork in the future.


Projects: HepatoSys

Genome Inform
Genome Inform 18: 54-64
12th Jun 2008

Ilka M Axmann, Stefan Legewie, Hanspeter Herzel

help Authors

[Stefan Legewie]

help Attributions


help Scales

Not Specified
Views: 2132
  • Created: 11th Sep 2012 at 13:01
  • Last updated: 24th Oct 2013 at 16:22

Related items


Log in / Register

Need an account?
Sign up

Forgotten password?

Front Page

Virtual Liver Network


Related Projects and friends

Imprint Taverna workflow workbench myExperiment JWS Online ISATAB myGrid Sabio-RK BioPortal Semantic SBML

Powered by:


Silk icons 1.3
Crystal Clear icons