Translation-level control of protein synthesis during early development

Early expression of a collagenase-like hatching enzyme gene in the sea urchin embryo.

“…Thus it has been argued that, as most of the proteins newly synthesized by the young embryo, the hatching enzyme was likely synthesized from a maternal mRNA stored in the unfertilized egg rather than from a zygotic message. This view was supported by experiments with RNA synthesis inhibitors (Terman and Gross, 1965) and with interspecific hybrids (Barrett and Angelo, 1969). Actually, studies with inhibitors were unreliable (Gross and Cousineau, 1963;Terman and Gross, 1965) and contradicted by experiments using the polyadenylation blocker cordycepin (Whiteley and Whiteley, 1975).…”

“…This view was supported by experiments with RNA synthesis inhibitors (Terman and Gross, 1965) and with interspecific hybrids (Barrett and Angelo, 1969). Actually, studies with inhibitors were unreliable (Gross and Cousineau, 1963;Terman and Gross, 1965) and contradicted by experiments using the polyadenylation blocker cordycepin (Whiteley and Whiteley, 1975). More recently Showman and Whiteley (1980) using hybrid andromerogones showed that expression of the embryonic genome was necessary for these hybrids to hatch.…”

“…The hatching enzyme, as a model to study gene expression during early development, has unique features: it is one of the few identified proteins which is newly synthesized well before the gastrula stage, it has a tightly controlled transient appearance and it catalyses a major developmental step. It has been discussed for a long time whether the mRNA coding for this enzyme is a maternal message stored in the unfertilized egg or a zygotic transcript synthesized from the embryonic genome during cleavage stages, but no definitive conclusion was reached (Gross and Cousineau, 1963;Terman and Gross, 1965; Barrett and Angelo, 1969;Showman and Whiteley, 1980). Whilst its existence has been demonstrated for a long time (Ishida, 1936) the enzyme itself was poorly known, as an adequately purified preparation was lacking.…”

Changes in Nucleic Acid Metabolism during Early Embryological and Fetal Growth

“…Such observations have shown that at any given time only a small fraction of the embryonic genome is func tional [11][12][13], In addition, quantitative and qualitative changes have been observed in the gene products; i.e., RNA, as development proceeds [14-lb]. It has also been demonstrated that when actinomycin D is administered for discrete periods to block gene transcription, specific effects on the mor phological and biochemical events of development occur [17][18][19].…”

Relative Effect of Transcription-Level and Translation-Level Control of Protein Synthesis during Early Development of the Sea Urchin

“…The sea urchin, A. punctulata, was obtained from Norris Hill, Duke Marine Laboratory, North Carolina, and handled as previously described. 4 Dactinomycin was obtained through the generosity of Dr. H. B. Woodruff of Merck, Sharpe and Dohme Co. Previous studies3 established that embryos exposed to 20 ,g/ml of Dactinomycin were effectively inhibited in synthesizing high molecular weight RNA.…”