A stochastic model for circadian rhythms from coupled ultradian oscillators

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dc.contributor.authorEdwards, Roderick
dc.contributor.authorGibson, Richard
dc.contributor.authorIllner, Reinhard
dc.contributor.authorPaetkau, Verner
dc.date.accessioned2014-02-24T21:52:05Z
dc.date.available2014-02-24T21:52:05Z
dc.date.copyright2007en_US
dc.date.issued2007-01-09
dc.descriptionBioMed Centralen_US
dc.description.abstractBackground: Circadian rhythms with varying components exist in organisms ranging from humans to cyanobacteria. A simple evolutionarily plausible mechanism for the origin of such a variety of circadian oscillators, proposed in earlier work, involves the non-disruptive coupling of pre-existing ultradian transcriptional-translational oscillators (TTOs), producing "beats," in individual cells. However, like other TTO models of circadian rhythms, it is important to establish that the inherent stochasticity of the protein binding and unbinding does not invalidate the finding of clear oscillations with circadian period. Results: The TTOs of our model are described in two versions: 1) a version in which the activation or inhibition of genes is regulated stochastically, where the 'unoccupied" (or "free") time of the site under consideration depends on the concentration of a protein complex produced by another site, and 2) a deterministic, "time-averaged" version in which the switching between the "free" and "occupied" states of the sites occurs so rapidly that the stochastic effects average out. The second case is proved to emerge from the first in a mathematically rigorous way. Numerical results for both scenarios are presented and compared. Conclusion: Our model proves to be robust to the stochasticity of protein binding/unbinding at experimentally determined rates and even at rates several orders of magnitude slower. We have not only confirmed this by numerical simulation, but have shown in a mathematically rigorous way that the time-averaged deterministic system is indeed the fast-binding-rate limit of the full stochastic model.en_US
dc.description.reviewstatusRevieweden_US
dc.description.scholarlevelFacultyen_US
dc.identifier.citationEdwards R, Gibson R, Illner R, Paetkau V. A stochastic model for circadian rhythms from coupled ultradian oscillators. Theor Biol Med Model. 2007 Jan 9;4:1. doi:10.1186/1742-4682-4-1en_US
dc.identifier.urihttp://www.tbiomed.com/content/4/1/1
dc.identifier.urihttp://dx.doi.org/10.1186/1742-4682-4-1
dc.identifier.urihttp://hdl.handle.net/1828/5185
dc.language.isoenen_US
dc.publisherBioMed Centralen_US
dc.subject.departmentDepartment of Mathematics and Statistics
dc.subject.departmentDepartment of Biochemistry and Microbiology
dc.titleA stochastic model for circadian rhythms from coupled ultradian oscillatorsen_US
dc.typeArticleen_US

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