Building a circadian clock model for Chlamydomonas reinhardtii

Alexander Skupin1 and Oliver Ebenhöh2

1) MPI of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam, Germany 2) Institute for Complex Systems and Mathematical Biology, University of Aberdeen, Aberdeen AB24 3UE, UK

Circadian rhythms are a widely used mechanism in many organisms to optimize cellular processes with respect to the periodic change of day and night. In mammals oscillations are generated by coupling of many neurons, whereas the clock in single cell organisms like cyanobacteria or E. coli is build by internal signaling networks. While the mechanism in cyanobacteria is rather well understood, a detailed understanding in Chlamydomonas is still missing. We use the Goodwin oscillator as a simple model to characterize the oscillations. We find strong evidences that Chlamydomonas may use inherent molecular fluctuations occurring by the stochastic nature of gene expression to generate an oscillatory behavior. On the basis of the study of Matsuo et al. we built a Chlamydomonas specific model for the clock including the transcriptional and translational level of the cell. This model allows for an analysis of the mRNA binding protein CHLAMY1 which is co-controlled by the chloroplast.

e-mail address of presenting author: skupin@mpimp-golm.mpg.de