SYNTHESIS OF RIBOSOMAL RNA DURING SEA URCHIN DEVELOPMENT .2. ELECTROPHORETIC ANALYSIS OF NUCLEAR AND CYTOPLASMIC RNAS

The kinetics of in vivo labelling of nuclear and cytoplasmic RNA has been studied by acrylamide gel electrophoresis in sea urchin embryos at the stages of blastula and gastrula. A rapidly labelled and slowly migrating RNA has been detected at both stages. Its specific activity reaches much higher levels in the nucleus than in the cytoplasm, where its decay is slower. The synthesis of a nuclear precursor of ribosomal RNA, particularly at the gastrula stage, is suggested. © 1969.