Structural Analysis and in Vitro Function of 80 s Ribosomes Isolated from Mouse Tumor Cells

Polyamine concentration, activity of the ribosomal dissociation factor and proportion of ribosomes active in protein synthesis in the 4-dimethylaminoazobenzene-induced rat hepatoma

4-Dimethylaminoazobenzene (DAB) induced liver tumour tissue showed a reduced proportion of ribosomes active in protein synthesis compared with control liver. Tumour cell extracts caused an increased association of ribosome subunits into inactive 80 S monomers, compared with the dissociation into active subunits caused by normal liver extracts. These findings may be explained, at least in part, by the increased proportion of spermidine to putrescine found in tumour tissue which would predispose towards association of the subunits.

Reassociation of eukaryotic ribosomal subunits by a factor from rat ascites hepatoma cytosol

Post-ribosomal supernatant extracts from Yoshida AH 130 ascites hepatoma cells promote the in vitro association of ribosomal subunits at low Mg2+ concentration. Comparable extracts from rat liver show, on the contrary, dissociation factor activity on ribosome monomers.