Use of new methods for construction of tightly regulated arabinose and rhamnose promoter fusions in studies of the Escherichia coli phosphate regulon

Novel methods were used for constructing tightly regulated rhamnose promoter and arabinose fusions in researches involving Escherichia coli phosphate regulon. The approaches involved uncoupling phoR and phoB expression from the normal controls by putting them behind the rhamnose-controlled PrhaB or foreign, arabinose-controlled ParaB promoter. The results showed that the the strains exhibited almost normal Pi control of the Pho regulon after induction of the corresponding delta-phoR and delta-phoB mutant containing either rhamnose or arabinose.