[Unidirectional orientation of the rpo B gene of E. coli cloned into filamentous M13mp8 and M13WB2348 phages]

Abstract

E. coli DNA fragment containing the rpoB gene with an rpoB3 rifampicin resistance dominant mutation (coding for the beta-subunit of RNA polymerase), genes rpI J and rpI L coding for the ribosomal proteins L7/L12 and L10, and promoters determining transcription of all these genes were cloned in M13mp8 and WB2348 filamentous phages. E. coli cells containing recombinant phages acquired resistance to rifampicin up to its 600 micrograms/ml concentration. When cloned into M13mp8 and WB2348 phages, the given fragment is oriented in such a way that the direction of the transcription initiated from its own promoter coincides with that initiated from the lac UV5 promoter. In both cases the recombinant phages have no stable rifampicin resistance which is coded by the fragment.