Similarity of ribosomal and ribosomal precursor RNA's from rat liver and the Novikoff ascites hepatoma.

Abstract

The 32P-labeled ribosomal RNA's and their precursors in rat liver and the Novikoff hepatoma have been examined by two competitive hybridization techniques and by nucleotide analyses. Significant differences were not found between the corresponding RNA of these tissues by competition of labeled RNA from the hepatoma with unlabeled 18 and 28 S ribosomal RNA and 28 and 45 S nucleolar RNA of liver and hepatoma by sequential or simultaneous competition hybridization. Differences were found in the specific activity of 32P-labeled nucleotides, but no significant differences were found by ultraviolet light absorbancy in the distribution of short oligonucleotides after digestion with pancreatic ribonuclease. These data provide evidence that the previously reported differences in nucleotide composition and oligonucleotide distribution were probably the result of nonuniform labeling rather than differences in the primary sequences. Accordingly, the primary structures of ribosomal RNA's and their precursors appear to be conserved in oncogenesis.