Radioactivity, apparently in cytonucleoproteins, from an amino acid-labeled nucleus implanted into a non-radioactive cell appeared in the host nucleus within 10 minutes, and the typical equilibrium ratio 70:30 donor nucleus radioactivity:host nucleus radioactivity was reached in 4 to 5 hours at 25°C. If such binucleates grew and divided, no localization of radioactivity was observable in cells fixed during mitosis, but the protein label remained concentrated in the daughter interphase nuclei for at least 4 generations. Continued migration of cytonucleoproteins was observed if these daughter nuclei were transplanted to other unlabeled cells. The Q10 (19° to 29°C) of the migration rate of radioactive cytonucleoproteins was ca. 1.3, suggesting that passage through the cytoplasm occurred by diffusion. Both non-migratory nuclear proteins and cytonucleoproteins appear to be synthesized in the cytoplasm.
THE CYTONUCLEOPROTEINS OF AMEBAE : II. Some Aspects of Cytonucleoprotein Behavior and Synthesis
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Thomas J. Byers, Dorothy B. Platt, Lester Goldstein; THE CYTONUCLEOPROTEINS OF AMEBAE : II. Some Aspects of Cytonucleoprotein Behavior and Synthesis . J Cell Biol 1 December 1963; 19 (3): 467–475. doi: https://doi.org/10.1083/jcb.19.3.467
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