title: Rifampin and rpoB mutations can alter DNA supercoiling in Escherichia coli.
abstract: Two cases are described which indicate that RNA polymerase could alter DNA supercoiling. One occurred in a topA mutant in which abnormally high levels of plasmid supercoiling were lowered by rifampin, an inhibitor of the beta subunit of RNA polymerase. The second case involves suppression of a temperature-sensitive gyrB mutation by a rifampin-resistant allele of rpoB, the gene encoding the beta subunit of RNA polymerase. Measurements of chromosomal DNA supercoiling show that the rpoB mutation reduced DNA relaxation.
authors.affiliation: Department of Biology, University of Rochester, New York 14627.
authors.forename: K
authors.initials: K
authors.lastname: Drlica
authors.forename: R J
authors.initials: RJ
authors.lastname: Franco
authors.forename: T R
authors.initials: TR
authors.lastname: Steck
mesh_terms: D004250:DNA Topoisomerases, Type II / Q000502:physiology; D004269:DNA, Bacterial / Q000187:drug effects*; D004278:DNA, Superhelical / Q000187:drug effects*; D012321:DNA-Directed RNA Polymerases / Q000235:genetics*; D004926:Escherichia coli / Q000187:drug effects / Q000235:genetics*; D009154:Mutation; D009690:Nucleic Acid Conformation / Q000187:drug effects; D012293:Rifampin / Q000494:pharmacology*
chemical_list: D004269:DNA, Bacterial; D004278:DNA, Superhelical; D012321:DNA-Directed RNA Polymerases; D004250:DNA Topoisomerases, Type II; D012293:Rifampin