Modeling and Parameter Estimation of the SOS Response Network in E.coli

The SOS response is an inducible DNA repair system that allows bacteria to survive in presence of an increased level of DNA damage. More than 40 genes are induced in response to DNA damage as part of the SOS regulon in Escherichia coli. Two main proteins play a key role in the regulation of this response: a repressor LexA that prevents the expression of these genes and an inducer RecA that induces the LexA cleavage reaction and the subsequent expression of the response genes. Most of these response genes are responsible for error-free DNA-damage repair and for the regulation of cell division. In this thesis we have investigated a network of nine genes including the principal mediators of the SOS response: lexA, recA, ssB, recF, dinI and umuDC and three sigma factor genes: rpoD, rpoH and rpoS.