• State: Published

Dependence of the period on the rate of protein degradation in minimal models for circadian oscillations

Exposure Information

Latest Exposure To the presentational view for the most recent revision of data reviewed and published from this workspace.

Workspace Summary

Circadian rhythms, which occur spontaneously with a period of about 24 h in a variety of organisms, allow their adaptation to the periodic variations of the environment. These rhythms are generated by a genetic regulatory network involving a negative feedback loop on transcription. Mathematical models based on the negative autoregulation of gene expression by the protein product of a clock gene account for the occurrence of self-sustained circadian oscillations. These models differ by their degree of complexity and, hence, by the number of variables considered. Some of these models can be considered as minimal because they contain a reduced number of biochemical processes and variables capable of producing sustained oscillations. In three of these minimal models, the period of the oscillations significantly changes with the rate of degradation of the clock protein. However, depending on the model considered, the period increases, decreases or passes through a maximum as a function of the protein degradation rate. We clarify the bases for these markedly different results by bringing to light the roles of (i) protein phosphorylation, which is required for protein degradation, and (ii) the velocity and degree of saturation of mRNA and protein degradation. Changes in the parameter values of the more complex of the minimal models can produce the period profiles observed in the other two models. The analysis allows us to reconcile the contradictory predictions for the dependence of the period on the clock protein degradation rate in three minimal models used to describe circadian rhythms.
Hanne Nielsen <>
URI for git clone/pull/push
Report an issue with this workspace


Filename Size Date Options
.DS_Store 6148 2011-09-07 [browse] 1064771 2011-09-07 [browse]
gerard_gonze_goldbeter_2009.cellml 30633 2011-09-07 [browse]
gerard_gonze_goldbeter_2009.html 3627 2011-09-07 [browse]
gerard_gonze_goldbeter_2009.png 14915 2011-09-07 [browse]
gerard_gonze_goldbeter_2009.session.xml 13523 2011-09-07 [browse] [run]
gerard_gonze_goldbeter_2009.svg 8977 2011-09-07 [browse]
gerard_gonze_goldbeter_2009.xul 16085 2011-09-07 [browse]
gerard_gonze_goldbeter_2009b.cellml 23006 2011-09-07 [browse]
gerard_gonze_goldbeter_2009b.session.xml 16550 2011-09-07 [browse] [run]
gerard_gonze_goldbeter_2009c.cellml 6870 2011-09-07 [browse]
gerard_gonze_goldbeter_2009c.session.xml 13533 2011-09-07 [browse] [run] 222368 2011-09-07 [browse]
goldbeter_1995.png 16513 2011-09-07 [browse]
goldbeter_1995.svg 9759 2011-09-07 [browse]
goldbeter_1995.xul 16697 2011-09-07 [browse] 112698 2011-09-07 [browse]
leloup_1999.png 59501 2011-09-07 [browse]
leloup_1999.svg 26222 2011-09-07 [browse]
leloup_1999_cropped.png 16315 2011-09-07 [browse]