Abstract
Insertion of HindIII DNA fragments into the HindIII site of plasmid pACYC184 destroys the promoter of the plasmid tetracycline resistance gene and causes Escherichia coli cells harboring recombinant plasmids to be tetracycline sensitive and chloramphenicol resistant. The HindIII-C DNA fragment of simian virus 40 contains the two virus promoters and the virus origin of replication. We report the isolation of recombinant plasmids that contained the simian virus 40 HindIII-C DNA fragment at the HindIII site but were capable of conferring tetracycline resistance to E. coli cells. The viral promoter sequences contained in the HindIII-C fragment presumably replaced the inactivated tetracycline resistance gene promoter sequences and enabled transcription of the tetracycline resistance gene.