Berlin 2012 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 22: Statistical Physics of Biological Systems III (with DY)
BP 22.5: Vortrag
Donnerstag, 29. März 2012, 16:00–16:15, H 1058
Modeling a Circadian Clock’s Slave Oscillator in Arabidopsis thaliana — •Christoph Schmal1,2, Dorothee Staiger1, and Peter Reimann2 — 1Molecular Cell Physiology, Faculty of Biology — 2Condensed Matter Theory, Faculty of Physics, Bielefeld University
Circadian clocks, generating self-sustained or slowly damped oscillations with a period of approximately 24 hours are usually described as transcriptional-translational feedback loops and can be found in nearly all eukaryotes and some prokaryotes. Entrainment by environmental signals, e.g., light, synchronizes the clock to the period of the Earth’s rotation.
It still remains unclear how the rhythmicity of the clock is transmitted to its output pathways. Slave oscillators could be candidates.
The RNA binding proteins AtGRP7 and AtGRP8 may represent such a slave oscillator. The transcription of both genes is rhythmically repressed by the partially redundant core oscillator genes LHY/CCA1 and they further shape their oscillatory profile via auto- and cross-regulating each other using an alternative splicing mechanism.
We model the system in terms of ordinary differential equations and estimate the barely known parameters with a cost function that quantifies the overlap between our model and key experimental features. Properties such as the waveform, the period and the phase of the oscillations, the mRNA and protein half-life and the response to varying photoperiods found in our simulations are compared with experimental findings. We make also suggestions and predictions for further experiments.