Global control of gene expression and adaptation to a changing environment
Lundi 30 septembre 2013 14:00
- Duree : 1 heure
Lieu : Salle des séminaires - LIPhy - Bât E - 140 Avenue de la Physique - St Martin d’Hères. Accès par interphone, appeler le secrétariat
Orateur : Hans GEISELMANN (Laboratoire Adaptation et Pathogénie des Microorganismes, UJF-CNRS UMR 5163, Université Joseph Fourier, Institut Jean Roget)
Living organisms must constantly adapt to a changing environment by adjusting internal, physiological parameters. We have studied the underlying principles in the bacterium Escherichia coli. The dynamical properties of cellular regulatory networks form the basis of this adaptive response. Gene expression is controlled by (i) the global physiological state of the cell, in particular the activity of the gene expression machinery, and (ii) DNA-binding transcription factors and other specific regulators. We have assessed their relative contributions in a circuit regulating the central carbon metabolism of Escherichia coli. Contrary to the widely held belief that the structure of the regulatory network is the dominant influence, we show that the dynamical response of the network is mainly controlled by the physiological state of the cell and global signaling molecules such as cyclic AMP (cAMP).
I will present our experimental and modeling approaches for elucidating the functioning of regulatory networks in E. coli. In particular, I will describe new methods for analyzing dynamics of regulatory networks, examples of communication within a bacterial population, and the optimization of resource allocation by the bacterium. Based on the our experimental and modeling results, we have re-engineered the probably most important function of a bacterium : the control of growth rate. I will discuss possible applications of this “synthetic biology” approach for fundamental and applied research.
Contact : bahram.houchmandzadeh@ujf-grenoble.fr
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