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DY: Fachverband Dynamik und Statistische Physik

DY 36: Statistical Physics in Biological Systems IV (joint with BP)

DY 36.8: Vortrag

Freitag, 15. März 2013, 11:30–11:45, H44

Impact of the cell division cycle on the dynamics of gene expression — •Veronika Bierbaum and Stefan Klumpp — Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Am Mühlenberg 1, 14476 Potsdam

Cell growth and division are elementary processes that influcence gene expression: While proteins are being synthesized, the change in cell volume due to cell growth leads to a dilution of protein concentration. To maintain a stable amount of protein, the protein content has to be doubled during the cell cycle. In this way, upon division, each daughter cell initiates the new cycle with the same amount of each protein. Protein synthesis and cell growth are typically not synchronous, such that the protein concentration varies over the cell division cycle. This variation may have an impact on the function of gene regulatory circuits.

We have developed a theoretical description of genetic regulatory systems that explicitly considers the cell division cycle to investigate its impact onto both simple and regulated systems of gene expression. We calculate the cell-to-cell variations in protein content of cells at different stages in the division cycle, and discuss to which extent these variations contribute to the extrinsic noise observed in single-cell experiments. While positive autoregulation can amplify the variation in protein concentration over the division cycle, negative autoregulation buffers against such variation. In addition, we investigate how the variability in the concentration influences the stability phases of bistable autoregulated systems.