Expression of E. coli genes carried by hybrids of plasmid RP4

Hybrids of the RP4 plasmid, containing bacteriophage Mu and chromosomal genes of Escherichia coli, were transferred into Salmonella typhimurium, Pseudomonas putida, Pseudomonas aeruginosa and Proteus mirabilis. The individual genes of the arginine, histidine, leucine and threonine operons were expressed in these microorganisms.