DIRECT EVIDENCE FOR NUCLEAR SYNTHESIS OF CYTOPLASMIC RIBOSE NUCLEIC ACID

Abstract
A more direct experimental design than has heretofore been employed was developed to test the hypothesis of nuclear synthesis of ribonucleic acid (RNA) and its transfer to the cytoplasm. The RNA of the nucleus was labeled with radioactive tracer, and the nucleus grafted into a cell with unlabeled RNA. Transmission of labeled material from nucleus to cytoplasm was then traced directly by auto-radiography. The evidence presented shows that RNA is synthesized in the nucleus and that RNA, or at least a nucleus-modified precursor of RNA, is transmitted to the cytoplasm.