title: Inducer-dependent conditional-lethal mutant animal viruses.
abstract: Regulatory elements of the Escherichia coli lac operon were used to construct an inducer-dependent conditional-lethal mutant animal virus. The gene encoding the repressor protein of the lac operon was integrated into the vaccinia virus genome so that it was expressed constitutively, and the lac operator was inserted next to the promoter of a gene that encodes an 11-kDa virion-associated protein of unknown function. The addition of inducer to the cell culture medium provided permissive conditions for isolation of a conditional-lethal mutant virus. Under nonpermissive conditions, the isolated virus did not form plaques, and the yield was decreased by at least 1000-fold under one-step growth conditions. Transcription of the operator-controlled gene was inducer-dependent and necessary for synthesis of the 11-kDa protein. Application of this mutagenesis strategy to other viruses is discussed.
authors.affiliation: Laboratory of Viral Diseases, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, MD 20892.
authors.forename: Y F
authors.initials: YF
authors.lastname: Zhang
authors.forename: B
authors.initials: B
authors.lastname: Moss
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D004926:Escherichia coli / Q000235:genetics; D005804:Genes, Lethal; D005822:Genetic Vectors; D007544:Isopropyl Thiogalactoside / Q000494:pharmacology*; D007763:Lac Operon; D008969:Molecular Sequence Data; D009154:Mutation; D015345:Oligonucleotide Probes; D016366:Open Reading Frames; D010957:Plasmids; D016133:Polymerase Chain Reaction; D011995:Recombination, Genetic; D015183:Restriction Mapping; D014158:Transcription, Genetic; D014616:Vaccinia virus / Q000187:drug effects / Q000235:genetics* / Q000502:physiology; D010948:Viral Plaque Assay; D014779:Virus Replication; D014780:Viruses / Q000235:genetics*
chemical_list: D015345:Oligonucleotide Probes; D007544:Isopropyl Thiogalactoside