Einbau und Ausbau von 32P im Nucleolus (nebst Bemerkungen über intra- und extranukleare Proteinsynthese)

Abstract

The incorporation of P32 into, and its loss from, the RNA of the nucleoli of Acetabularia occurs rapidly and intensively. In combination with other studies it is concluded: (1) that the RNA in the nucleolus of mature nucleoli has a high conversion rate; (2) that the RNA neither migrates into the nucleolus from the outside nor migrates outward from it in appreciable amounts, particularly not into the cytoplasm; (3) that the nucleolus is a place of protein synthesis within the nucleus. Nevertheless, there is as yet no evidence that proteins synthesized in the nucleus are of real significance for the formation of extranuclear proteins (cytoplasm and chloroplasts). These, rather, are synthesized outside of the nucleus.