Dresden 2011 – wissenschaftliches Programm
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BP: Fachverband Biologische Physik
BP 1: Statistical Physics in Biological Systems I (joint DY, BP)
BP 1.5: Vortrag
Montag, 14. März 2011, 11:45–12:00, ZEU 250
Heterogeneous timing of gene induction as a regulation strategy — •Noreen Walker1,2, Georg Fritz1,2, Sonja Westermayer2, Judith Megerle2, Joachim Raedler2, and Ulrich Gerland1,2 — 1Arnold Sommerfeld Center for Theoretical Physics — 2Department of Physics, Ludwig-Maximilians-Universität München, Theresienstr. 37, 80333 München
Heterogeneity within a genetically homogeneous population is a common phenomenon in nature. While it has long been known that noise in gene expression leads to heterogeneity in protein levels, recent studies also demonstrated heterogeneity in the timing of gene induction. When a colony of E. coli cells is suddenly exposed to a new sugar, the onset time for expression of the specific sugar utilization system is broadly distributed, if the sugar concentration is low [1]. Whereas the underlying mechanism has been characterized [1], it is currently unclear whether this heterogeneous timing is a side effect or a genuine strategy to optimize growth and survival. Here, we first present further experimental evidence for heterogeneous timing. We then perform a theoretical analysis of the cost and benefit of different regulation strategies for gene induction within a coarse-grained growth model. We find that at low sugar concentrations, heterogeneous timing can indeed be an optimal regulation strategy, while a homogeneous response is favorable at high sugar concentrations.
J. Megerle et al., Biophys. J. 95, 2103-2115 (2008)