Regensburg 2016 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 28: Systems Biology & Gene Expression and Signalling

BP 28.2: Vortrag

Dienstag, 8. März 2016, 10:00–10:15, H44

Modeling of Colicin E2 Expression — •Matthias Lechner¹, Mathias Schwarz², Madeleine Opitz¹, and Erwin Frey¹ — ¹Arnold Sommerfeld Center for Theoretical Physics (ASC) and Center for NanoScience (CeNS), Department of Physics, Ludwig-Maximilians-Universität München — ²Institute for Biological and Medical Imaging, Technische Universität München and Helmholtz Zentrum München, Neuherberg, Germany

Regulation of mRNA translation plays a crucial role in many bacterial pathways. For this purpose, possible regulatory components are small, non-coding RNAs (sRNAs) or mRNA-binding proteins. An important system that includes a combination of these modes is the Colicin E2 system, in which SOS responses trigger the expression of the toxin colicin and its release protein. We present a simple, yet comprehensive, model of the colicin E2 regulatory network, and study both its deterministic and stochastic dynamics in detail. Its regulation can be reduced to three components: free mRNA, the mRNA-binding protein CsrA, and an effective sRNA that regulates CsrA. For the stationary state, we show that the production rate of sRNA tunes the magnitude of intrinsic fluctuations and the sharpness of mRNA thresholds. To study the dynamics, we incorporate a stochastic SOS response system into our model. The CsrA regulation filters out short-lived activation peaks, and delays the release of toxin after prolonged SOS signals. Our model thus describes Colicin E2 expression dynamics in detail and reveals the importance of the specific components for toxin release. Moreover, we give an outlook on the role of further components.