title: Evidence for the existence of two forms of RNA polymerases I and II in insect wing epidermis.
abstract: DNA-dependent RNA polymerases were solubilized from developing wings of the oak silkmoth, Antheraea pernyi, and partially purified by ion-exchange chromatography and sucrose gradient sedimentation. Four enzyme species were resolved on the basis of chromatographic behavior, divalent cation requirements, ionic strength optima, template preference and alpha-amanitin sensitivity. Each class (i.e. RNA polymerase I and II) was present in two forms termed IA, IB and IIA, IIB on the basis of their elution pattern from the column. Both class I enzymes were sensitive to high concentrations of alpha-amanitin but this may be due to general toxicity rather than specific inhibition. The intraclass variants did not differ significantly in enzymatic properties although form IIB was more sensitive to alpha-amanitin (50% inhibition at 2 . 10(-9) M) than form IIA (3 . 10(-8)M).
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D007527:Isoenzymes / Q000302:isolation & purification / Q000378:metabolism*; D007700:Kinetics; D007915:Lepidoptera / Q000201:enzymology*; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009036:Moths / Q000201:enzymology*; D012318:RNA Polymerase I / Q000302:isolation & purification / Q000378:metabolism*; D012319:RNA Polymerase II / Q000302:isolation & purification / Q000378:metabolism*; D012867:Skin / Q000201:enzymology
chemical_list: D000546:Amanitins; D007527:Isoenzymes; D008345:Manganese; D012319:RNA Polymerase II; D012321:DNA-Directed RNA Polymerases; D012318:RNA Polymerase I; D008274:Magnesium