期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1976
卷号：73
期号：4
页码：1029-1033
DOI：10.1073/pnas.73.4.1029
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Three peaks of DNA-dependent RNA polymerase (RNA nucleotidyltransferase) activity are resolved by chromatography of a sonicated yeast cell extract on DEAE-Sephadex. The enzymes, which are named RNA polymerases I, II, and III in order of elution, show similar catalytic properties to the vertebrate class I, class II, and class III RNA polymerases, respectively. Yeast RNA polymerase III is readily distinguished from yeast polymerase I by its biphasic amnonium sulfate activation profile with native DNA templates, greater enzymatic activity with poly[d(I-C)] than with native salmon sperm DNA, and distinctive chromatographic elution positions from DEAE-cellulose (0.12 M ammonium sulfate) compared with DEAE-Sephadex (0.32 M ammonium sulfate). The three yeast RNA polymerases also show significant differences in alpha-amanitin inhibition. RNA polymerase II is the most sensitive (50% inhibition at 1.0 mug of alpha-amanitin per ml). Contrary to the results for vertebrate systems, yeast polymerase I can be completely inhibited by alpha-amanitin at high concentrations (50% inhibition at 600 mug/ml) while yeast RNA polymerase II BEGINS TO SHOW SIGNIFICANT INHIBITION ONLY AT CONCENTRATIONS EXCEEDING 1 MG/ML. Therefore, yeast RNA polymerases I and III show a pattern of alpha-amanitin sensitivity that is the reverse of that seen for the analogous vertebrate RNA polymerases.
