Modelling bacterial alternative sigma factors and their competition
Bacteria have been reported to exploit the seemingly adverse noise in gene expression to achieve biologically important dynamical behaviours. They can create phenotypic heterogeneity by stochastically turning on the expression of certain genes which allow them to "hedge their bet" within a genetically homogenous population to better survive a stressful environment. Here we demonstrated that a variety of dynamical behaviours (e.g., stochastic pulsing, oscillation, and heterogenous expression) can be achieved by a simple stochastic differential equation model based on molecular mechanisms. The model further shows that the competition between Sigma factors for the core RNA polymerase could give rise to the apparent cooperativity, which is crucial to multiple biologically relevant behaviours.
The thesis is under the mentorship of Dr James Locke (Principle investigator, Sainsbury Laboratory Cambridge University) and Dr Torkel Loman.
The thesis was submitted in August 2021. Submitted version. The date of last edit is shown in the most up-to-date version.