title: RNA synthesis in isolated bovine thyroid nuclei and nucleoli. alpha-Amanitin effect, a hint to the existence of a specific regulatory system.
abstract: DNA dependent RNA polymerase activities in isolated bovine thyroid nuclei and nucleoli have been studied. They retain their RNA synthetic activity for an extended period of time. This RNA synthetic activity is sensitive to actinomycin D and requires the presence of all four ribonucleoside triphosphates. The optimal conditions have been determined. Polyacrylamide gel electrophoresis reveals that the RNA synthesized has a size distribution ranging from 34S to 4S. The production of 18S-8S RNA is very sensitive to low concentrations of alpha-amanitin. However, in isolated bovine thyroid nuclei (not in nucleoli) this drug displays an effect on all RNA classes produced. The alpha-amanitin induced drastic decrease of [3H]-UMP incorporation in RNA of all sizes synthesized by isolated bovine thyroid nuclei is discussed.
mesh_terms: D000546:Amanitins / Q000494:pharmacology*; D000818:Animals; D002417:Cattle; D002466:Cell Nucleolus / Q000187:drug effects / Q000378:metabolism*; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D007700:Kinetics; D008274:Magnesium / Q000494:pharmacology; D008345:Manganese / Q000494:pharmacology; D009994:Osmolar Concentration; D012313:RNA / Q000096:biosynthesis*; D012260:Ribonucleases / Q000378:metabolism; D013961:Thyroid Gland / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects*
chemical_list: D000546:Amanitins; D008345:Manganese; D012313:RNA; D012260:Ribonucleases; D008274:Magnesium