Autoradiographic studies were made of the effects of inhibitors of protein synthesis on the incorporation of 3H-uridine into HeLa cells grown in monolayer culture. Both puromycin and cycloheximide inhibited the incorporation of uridine into the nucleolus, while the non-nucleolar portion of the nucleus was relatively spared from the inhibitory effect. The subsequent appearance of label in the cytoplasm was severely depressed by the inhibitor. It was noted that cycloheximide must be used at higher concentration than puromycin to achieve a comparable effect on incorporation of 3H-lysine into protein or 3H-uridine into RNA. These experiments are taken to imply that protein synthesis is necessary for the formation of stable ribosomal RNA in the nucleolus, and therefore for its appearance in the cytoplasm. It is suggested that protein component of the ribosome is necessary for the stabilization of ribosomal RNA in HeLa cells.
All Science Journal Classification (ASJC) codes
- Cell Biology