title: [Mutations in the Escherichia coli RNA-polymerase beta-subunit gene cloned in a multicopy plasmid].
abstract: A multicopy plasmid pLMN1 expressing a wild type rpoB gene encoding Escherichia coli RNA polymerase beta subunit gene was constructed. Introduction of this plasmid into rifampicin-resistant RpoB mutants makes them rifampicin-sensitive. Rifampicin-resistant clones appear in such strains with frequencies up to 10(-3), due to recombinational (recA-dependent) transfer of rif-r mutations from chromosome to pLMN1. This provides a simple selection procedure for transfer of any rpoB mutation, together with a rif-r mutation from a chromosome to pLMN1. In this way, we transferred rpoB22 amber mutation to pLMN1 for localization of the mutant codon by DNA sequencing.
authors.forename: E P
authors.initials: EP
authors.lastname: Ogryz'ko
authors.forename: V G
authors.initials: VG
authors.lastname: Nikiforov
mesh_terms: D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004352:Drug Resistance, Microbial; D004926:Escherichia coli / Q000201:enzymology / Q000235:genetics*; D005786:Gene Expression Regulation; D005798:Genes, Bacterial; D005822:Genetic Vectors; D009154:Mutation; D010957:Plasmids; D012293:Rifampin / Q000494:pharmacology
chemical_list: D012321:DNA-Directed RNA Polymerases; D012293:Rifampin
vernacular_title: Poluchenie mutatsiĭ v ékspressiruiushchemsia gene beta-sub''edinitsy RNK-polimerazy Escherichia coli, klonirovannom v mnogokopiĭnoĭ plazmide.