Partial purification and characterization of DNA-dependent RNA polymerases I and II from cherry salmon ( Oncorhynchus masou)

Abstract

1. 1. DNA-dependent RNA polymerases I and II were purified approx 3900- and 13,000-fold, respectively, from sonicated nuclear extract of cherry salmon ( Oncorhynchus masou) liver by DEAE-Sephadex, heparin-Sepharose and DNA-cellulose column chromatography. 2. 2. The purified RNA polymerases exhibited a requirement for four kinds of ribonucleoside 5′-triphosphates, an exogeneous template and divalent cation. 3. 3. The activities of RNA polymerases I and II were inhibited by Actinomycin D (24 μg/ml) but not by Rifampicin (200 μg/ml). 4. 4. RNA polymerase I preferred native DNA as template, while polymerase II preferred single-stranded DNA. 5. 5. RNA polymerase II was inhibited by a low concentration of α-amanitin (0.02 μg/ml). RNA polymerase I was also inhibited by the relatively high concentration of α-amanitin (IC 50 = 100 μg/ml and IC 70 = 750 μg/ml). 6. 6. RNA polymerases from cherry salmon exhibited a higher activity at low temperature than from rat liver.