Uptake of exogenous ribonucleic acid by ascites tumor cells. I. Autoradiographic and chromatographic studies

Ascites tumor cells are able to ingest a labeled heterologous RNA which is dissolved in their incubation medium. The maximum quantity taken up after 40 min of incubation represents 2-4 per cent of the normal RNA content of those cells. Autoradiographic study shows that the RNA taken up is mainly located in the nucleus and the cytoplasm of the cells. Far less is fixed by the nucleolus. The base composition as well as the chromatographic behaviour on DEAE-cellulose paper of the exogenous RNA (yeast RNA) seem to be maintained after ingestion by the cells. The results suggest that ascites tumor cells can take up intact RNA, without greatly modifying its structure and composition. The mechanism of this RNA uptake has not yet been clarified.