A study on the rna polymerase activities in bovine thyroid nuclei isolated in isotonic sucrose, hypertonic sucrose or in anhydrous glycerol media: Influence of the isolation procedure on the electrophoretic pattern of acid soluble nuclear proteins

Abstract

1. 1. After differential pelleting of bovine thyroid bound RNA polymerase II was the more enriched enzyme activity in the nuclear fraction, and coincided best with the DNA profile. 2. 2. The RNA polymerase I + III activity was compared in nuclear fractions isolated either in 0.25 M sucrose (wet tissue) or in anhydrous glycerol (lyophilized tissue) or in 2.4 M sucrose (lyophilized tissue). 3. 3. Although the nuclei were more resistant to the isolation porcedure in glycerol, more proteins were extracted by that procedure than during the isolation in 2.4 M sucrose. 4. 4. With the 2.4 M sucrose method a twofold enrichment of RNA polymerase I + III activity in respect to DNA occurred in the nuclei pointing to an exclusive localization of these activities within the nucleus. 5. 5. Using the same isolation procedure the different classes of histones were better resolved upon polyacrylamide gelelectrophoresis.