Cloned seventeen-nucleotide-long synthetic lactose operator is biologically active

A 17-nucleotide-long synthetic DNA molecule constituting the minimal recognition sequence of the lactose operator has been cloned in E. coli using the vehicle pBR313 and a synthetic HindIII adaptor. The clones containing the lac-pBR313 hybrid DNA constitutively produced beta-galactosidase. The level of beta-galactosidase was high and comparable to that obtained in cells carrying a 21-nucleotide-long synthetic lac operator on pMB9 plasmid or cells carrying a natural lac operator on pOP203-1 plasmid.