Combining Theory and Experiments to Understand Sugar Regulation in Bacteria
Szabolcs Semsey and Sandeep Krishna
Affiliation: National Centre for Biological Sciences, Bangalore, India.
Keywords: Dominant negative autoregulation, dynamic transitions, feedback loops, galactose regulatory network.
In this review we discuss the interaction between experiments and theory in understanding regulatory systems
in bacterial cells, using the galactose network of E. coli as a model system to illustrate this. Initially, experiments led to a
coarse-grained network view of this system, which revealed the structure of entangled negative and positive feedback
loops that regulates galactose metabolism. A dynamical model, based on this network picture and in vitro experiments, indicated
that one of the main regulators would have little role to play in any steady-state scenarios. The dynamical experiments
this result suggested revealed the intricate timing sequence of gene expression in situations of rapidly decreasing
galactose. All this information is slowly coming together to form a picture of how the different elements of the galactose
regulatory system work together to regulate metabolism in the presence of fluctuating and changing food sources.
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