Dresden 2009 – wissenschaftliches Programm
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DY: Fachverband Dynamik und Statistische Physik
DY 2: Statistical physics in biological systems I (joint session DY/BP)
DY 2.8: Vortrag
Montag, 23. März 2009, 12:45–13:00, ZEU 255
A simple model for stress reactions in cellular regulation — •Andreas Ruttor1, Guido Sanguinetti2, Cedric Archambeau3, and Manfred Opper1 — 1Technische Universität Berlin, Germany — 2University of Sheffield, UK — 3University College London, UK
Microarray experiments show that some cells can quickly respond to external stimuli, e.g. sudden environmental changes, by switching between different regulatory regimes. This stress reaction is achieved by activating a transcription factor, which changes the transcription rates of certain proteins. We present a simple model for such a bistable regulatory system. Production and degradation of mRNA and proteins are described by differential equations, as their concentrations change continuous in time. But we assume that there are only two possible states for the transcription factor, either active or inactive. Therefore its activity, which is difficult to observe in microarray experiments, is modelled as a random telegraph process. We find that this stochastic process can be reconstructed using only noisy measurements of the mRNA concentrations at discrete points in time. Our solution to this problem is based on calculating effective jump rates for the hidden activity of the transcription factor. This can be done by using the backward Chapman-Kolmogorov equation directly or an efficient approximate algorithm. Afterwards it is possible to estimate the time evolution of the posterior process and parameters of the regulatory system. Simulation results indicate that our approach works well.