Regulatory protein from a restriction-modification system interferes with E. coli global regulatory networks, revealing an unexpected link between excision of a cryptic Rac prophage and lipopolysaccharide biosynthesis defects

We show here that E. coli rewires its regulatory network, so as to minimize the adverse regulatory effects of the imported C TF. This complex set of interactions may reflect the ability of bacteria to protect themselves by having robust mechanisms to maintain their regulatory networks, and/or suggest that regulatory C proteins from mobile operons are under selection to manipulate their host's regulatory networks for their own benefit.We subcultured MG1655 rac + cells carrying the p24 plasmid (with csp231IC under its natural promoter) for many generations by daily passaging. About 75 cell generations produced almost 90% colonies with round and regular shapes, losing the initial phenotype. We took nine such colonies and one control colony (prior to p24 plasmid introduction), isolated their genomes and subjected all 10 to whole genome sequencing.