A study of ribosomes during embryonic development of Xenopus laevis

The ribosomes of Xenopus laevis were studied during embryonic development. The RNA of the ribosomal fraction constituted only 20% of the total RNA. Approx. 70% of the total RNA of eggs is found in the first sediment of centrifugation. If the supernatant containing ribosomes is centrifuged on a sucrose gradient, at a concentration of 10-3 M Mg2+ only one peak is detectable. During the embryonic development, the sedimentation constant of ribosomes is approx. 70 S. The base composition of ribosomes reveals the usual high G-C content. © 1965.SCOPUS: ar.j