Appearance of radioactivity in mouse cells after administration of labeled macromolecular RNA.

Although various induced effects have been reported to follow administration of ribonucleic acid, direct evidence of cellular uptake has been lacking. Radioautographic evidence is presented of incorporation of label from radioactive macromolecular RNA presented to normal and neoplastic mouse cells. Although most of the label appeared in cellular RNA, deoxyribonucleic acid also was occasionally labeled. This suggested that at least partial degradation of the RNA occurred prior to or after incorporation.