Ribonucleic Acid

Abstract

As we have already mentioned, immediately upon fertilization the sea urchin egg undergoes a tremedously high rate of cell division not accompanied by embryonic growth, at least until the prism stage. In order to be able to do so, it has stored in its cytoplasm a number of macromolecules synthesized during oogenesis: among these, ribosomal RNA (Sconzo et al., 1972; Giudice et al., 1972b; Griffith et al., 1981). Ribosomal RNA synthesis, therefore, is barely detectable during cleavage and becomes apparent at the gastrula stage (Nemer, 1963; P. R. Gross et al., 1965; Comb et al., 1965b; Giudice and Mutolo, 1967, 1969; Barros and Giudice, 1968; Sconzo et al., 1970a, b; Sconzo and Giudice, 1971; Greco et al., 1977).