Final Activity Report Summary - QUMGAR (Quantitative modeling of the gal regulon)
Bacteria sense a wide array of signals (minerals, nutrients, stress signals, etc.). A large class of cellular response systems regulates the flux and concentration of small molecules by controlling their transport and metabolism. Many of the genes encoding components of such response systems are regulated by two or more signals, therefore the cell needs to integrate environmental signals and compute the optimal gene expression levels. In this work we used the galactose utilisation system of Escherichia coli to study signal integration at the level of promoter transcription.
We combined the transcriptional network of the galactose regulon, obtained from our experiments, with literature data to construct an integrated map of the galactose network. Input functions (the correlation between the levels of input signals and the promoter activity) were determined by a multidisciplinary approach, combining biochemical and genetic experiments with computation. Input functions of the galactose system promoters are diverse.
We observed simple shapes resembling Boolean logic gates and more complex shapes that can be approximated by the combination of different simple logic gates. The response range of input functions shows good agreement with the potential physiological range of the input signals.
We combined the transcriptional network of the galactose regulon, obtained from our experiments, with literature data to construct an integrated map of the galactose network. Input functions (the correlation between the levels of input signals and the promoter activity) were determined by a multidisciplinary approach, combining biochemical and genetic experiments with computation. Input functions of the galactose system promoters are diverse.
We observed simple shapes resembling Boolean logic gates and more complex shapes that can be approximated by the combination of different simple logic gates. The response range of input functions shows good agreement with the potential physiological range of the input signals.