The RNA polymerase II of an alpha-amanitin-resistant Chinese hamster ovary cell line.
Amal, an alpha-amanitin-resistant mutant of the Chinese hamster ovary cell line, contains an RNA polymerase activity which elutes from DEAE-Sephadex at a salt concentration characteristic of an RNA polymerase II, but which is not sensitive to alpha-amanitin at levels where the polymerase II of wild-type cells is strongly inhibited. This result suggests that Amal owes its amanitin-resistant phenotype to a mutation affecting one of its genes for RNA polymerase II. To test this hypothesis, we purified the enzyme from Amal and then compared its properties with those of the wild-type enzyme. The mutant enzyme is indeed a polymerase II, and is over 600 times less sensitive to alpha-amanitin and more thermolabile than the wild-type enzyme.
D000546:Amanitins / Q000494:pharmacology*; D002460:Cell Line; D003429:Cross Reactions; D004247:DNA; D012321:DNA-Directed RNA Polymerases / Q000276:immunology / Q000378:metabolism*; D004351:Drug Resistance; D006358:Hot Temperature; D009154:Mutation; D009691:Nucleic Acid Denaturation
D000546:Amanitins; D004247:DNA; D012321:DNA-Directed RNA Polymerases