The repertoire of DNA-binding transcriptional regulators in Escherichia coli K-12

Using a combination of several approaches we estimated and characterized a total of 314 regulatory DNA-binding proteins in Escherichia coli, which mig ht represent its minimal set of transcription factors. The collection is co mprised of 35% activators, 43% repressors and 22% dual regulators. Within m any regulatory protein families, the members are homogeneous in their regul atory roles, physiology of regulated genes, regulatory function, length and genome position, showing that these families have evolved homogeneously in prokaryotes, particularly in E.coli, This work describes a full characteri zation of the repertoire of regulatory interactions in a whole living cell. This repertoire should contribute to the interpretation of global gene exp ression profiles in both prokaryotes and eukaryotes.