[The inducing capability of nucleic acids tested on amphibian ectoderm]

Ribonucleic acids were extracted from chick- andTriturus embryos by the phenol method and tested for their inducing ability:Ribonucleic acids from chick embryos had only a weak inducing capacity compared with that exerted by inducing chick embryo protein fractions. In tissue cultures of undetermined amphibian ectoderm they induced unspecific neural structures, mesenchymal cells and melanophores only to a small extent. But the differentiated part of the tissue was still higher than in control series where the ectoderm was cultivated in Flickinger solution alone. If the protein content of the RNA fractions is reduced by zone-electrophoresis or shaking with chloroformoctanol, the inducing ability of the RNA further decreases. Inactive proteins added to the RNA-containing solutions did not promote their inducing ability.Ribonucleic acids fromTriturus embryos including m-RNA had only a weak inducing capacity too.RNA fractions from chick embryo nuclei, containing much DNA and some proteins in addition to their RNA, had a higher inducing capacity (but still much less than had active proteins). Neural structures and complexes of cylindrical cells with basally located nuclei were induced.