Stimulation of Protein Synthesis in the Mitochondria of Sea Urchin Embryos before Gastrulation: (protein synthesis/sea urchin embryo/mitochondria/peptide elongation factor/mitosol).

ABSTRACT

A transient increase in protein synthesis was observed in mitochondria at the mesenchyme blastula stage of sea urchin (Hemicentrotus pulcherrimus) embryos. This stimulated activity was inhibited by chloramphenicol but not by cycloheximide. Reconstituting experiments in which poly U-dependent protein synthesis was carried out showed the mitochondrial peptide elongation factor to be essential for increasing the protein synthetic activity in mesenchyme blastula, but aminoacyl tRNA synthetase and ribosome fraction containing initiation factor not to be involved in this increase. These findings are discussed in relation to the differentiation of embryos at the gastrulation stage.