32P Nucleotide Composition of Nuclear and Nucleolar RNA of Morris Hepatomas

Summary Nuclei and nucleoli were isolated from a number of types of minimal deviation hepatomas. The nuclear preparations from hepatomas 9618A, 9618B, 9121, 9108A, 7794, and 7787 were equal in purity to those obtained from normal liver. The nuclear preparations from hepatomas 9098, R7, 8995, and others were similar to those obtained from tumors transplanted for long periods, i.e., the nuclear preparations contained perinuclear cytoplasmic tags. Nucleolar preparations of purity equal to those of normal liver and other tumors were obtained in sufficient yield for analysis of 32 P nucleotide compositions from hepatomas 9618A, 9618B, 9121, 9098, and 7787. The 32 P nucleotide compositions of nuclear 45 S RNA of the Morris hepatomas varied from those rich in guanylic and cytidylic acids and low in adenylic acid, like those of the Walker tumor and other tumors transplanted for long periods, to those richer in adenylic acid and lower in cytidylic acid, which are more similar to the 32 P base compositions of nuclear 45 S RNA of regenerating liver. The 32 P nucleotide compositions of the nucleolar 45 S RNA of the Morris hepatomas was like that of other tumors previously studied (28), i.e., the content of adenylic acid was low and the content of cytidylic acid was high. Along with the results of previous studies, these data suggest that there are common nucleotide compositions of the newly synthesized nucleolar RNA (45 S RNA) of tumor cells.