Ribosomal proteins of hamster, mouse and hybrid cells

We hhave been analyzing what could be considered to be structural ribosomal proteins, that is, those that remain with the ribosome when it has been subjected to centrifugation through 1.75 M sucrose, treatment with puromycin and KCl, and centrifugation through 0.5 M KCl and sucrose. By two-dimensional gel electrophoresis, a mouse-specific protein and a Syrian hamster-specific protein are detected, using liver or cultured cell lines. With liquid scintillation counting after two-dimensional gel electrophoresis it is possible to estimate the proportion of species-specific ribosomal protein in a mouse-hamster somatic cell hybrid.