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BP: Fachverband Biologische Physik

BP 4: DNA \& DNA Enzymes

BP 4.3: Talk

Monday, March 14, 2011, 14:45–15:00, ZEU 260

A model for the degradation of messenger RNA in bacteria — •Carlus Deneke, Angelo Valleriani, and Reinhard Lipowsky — Max-Planck-Institut für Kolloid- und Grenzflächenforschung, Department of Theory and Bio-Systems, Potsdam, Germany

In a cell, the amount of messenger RNA (mRNA) is kept in balance by the processes of transcription and degradation. In the bacterium E. coli, the stability of mRNA is limited due to the action of protein complexes called the degradosome. They consist of several endo- and exonucleases which cooperatively degrade the mRNA chain until it is eventually fully recycled.

In this contribution, we present a theoretical model that takes into account the stochastic nature of this process. To build the model, we have assumed that in bacteria the main degradation pathway is initiated by endonucleolytic cleavage, according to the standard view in the field. It exploits the fact that the coverage of mRNA with ribosomes depends on the age of the transcript and that ribosomes shield the transcript against degrading proteins.

One consequence of the model is that the mean life time of the transcripts decreases with the length of the coding sequence. This conclusion is in agreement with many experimental half-life measurements. We will show a comparison of our model to experimental half-life data and critically discuss the nature of these data.