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BP: Fachverband Biologische Physik

BP 20: Regulation and Signaling

BP 20.6: Talk

Thursday, February 28, 2008, 11:15–11:30, C 243

On the effect of transcription factor fluctuations at promoter logic gates — •Christian Fleck, Moritz Gerstung, and Jens Timmer — Institute of Physics, Hermann-Herder-Str. 3a, University of Freiburg, Germany

Biological organism constantly respond to changing cellular and environmental signals. These signals are integrated at cis-regulatory modules or promoter logic gates. Hence, the output causally depends on the degree of occupancy of the individual target sides within the cis-regulatory module. Because many TFs are present in low copy numbers per cell, the regulatory processes are inevitably subject to noise. A substantial preliminary for an understanding of how noise alters the output of promoter logic gates is knowledge about how fluctuations in TF abundance affect single operator occupancy. The inherent non-linearity arising from the bimolecular interaction impedes the analytical investigation of this phenomenon substantially. We present a detailed analysis of a TF-operator interaction finding noise correction terms to the macroscopic description. While the correction is always negative for single binding sites, we discover more diverse effects on the logic gates comprising multiple binding sites.