In vitro Uptake of Isotopically Labeled RNA by Mammalian Spleen Cells. ∗

Abstract

Summary

Suspensions of rat spleen cells were found to incorporate P³² labeled rat spleen RNA. A maximal incorporation of 2.4% of the input RNA was obtained when 4 × 10⁷ viable cells were cultured in the presence of 200 μg of P³² labeled RNA. Larger amounts of RNA appear to inhibit uptake. It was shown also that the uptake of P³² labeled RNA is competitively inhibited by unlabeled RNA, and that inhibition of uptake is proportional to the competitive RNA concentration. It was concluded that the majority of the radioactivity obtained from treated cells may be attributed to the uptake of RNA.