RNA metabolism in embryonic development and differentiation. I. Fertilization and after

Gastrulation in the sea urchin Strongylocentrotus purpuratus is blocked by the fluorescein dye erythrosin B

Erythrosin B, a food, drug, and cosmetic dye, arrested gastrulation in embryos of the sea urchin Strongylocentrotus purpuratus. A 30 min pulse of 5 microM erythrosin B added at 18 hr postinsemination blocked gastrulation scored at 50 hr postinsemination when control embryos had completed gastrulation. Dye addition at later times had no detectable effects on development through 50 hr postinsemination. The dye may block primary invagination via its known effects on plasma membrane permeability and fluidity.

Maternal histone messenger RNA: detection by molecular hybridization

A competition-hybridization assay has been developed for the majority of sequences present in embryonically synthesized histone messenger RNA. The assay permits the first direct demonstration of specific "maternal" messengers in unfertilized sea-urchin eggs. The molecular size of histone messenger RNA stored in the egg appears to be the same as that of histone messenger RNA synthesized by the embryo. Maternal histone messenger RNA is found in the soluble phase of egg homogenates, in the form of ribonucleoprotein particles, unassociated with ribosomes.