Computer simulation of stochastic phenotypic switching in bacteria 

Andrzej M. Kierzek
School of Biomedical and Molecular Sciences, University of Surrey
Guildford, GU2 7XH, UK
a.kierzek@surrey.ac.uk, http://www.sysbio.pl/

Gene expression processes frequently involve small numbers of molecules (e.g. a few molecules of a transcriptional regulator binding to one `molecule' of a DNA regulatory region) and are subjected to significant stochastic fluctuations. The influence of the transcription and translation initiation frequencies on the magnitude of these fluctuations will be described. Other mechanisms of the regulation of gene expression such as transcriptional and translational feedback loops will also be mentioned in this context. Subsequently, detailed kinetic models of two component system signalling and glucose, lactose and glycerol metabolism in Escherichia coli will be used to illustrate an influence of stochastic effects in gene expression on the function of metabolic processes. It will be shown that random fluctuations in gene expression propagate through the positive and negative feedback loops in the complex biochemical reaction network and cause epigenetically inherited changes in the physiology of single bacterial cells.