title: Increase in eukaryotic initiation factor 2B activity following fertilization reflects changes in redox potential.
abstract: One of the factors involved in the postfertilization activation of protein synthesis in the sea urchin, Strongylocentrotus purpuratus, is the activation of eIF-2B, the initiation factor responsible for guanine nucleotide exchange on eIF-2. Cell-free translation systems from unfertilized eggs are stimulated by added eIF-2B, although this dependency is rapidly lost in translation systems prepared at various times following fertilization. Cell-free translation systems prepared from unfertilized eggs show significantly lower eIF-2B activities than those prepared from 2-h embryos. However, the provision of an NADPH regeneration system significantly stimulates eIF-2B activity in egg extracts and, in addition, stimulates both binding of initiator tRNA to the small ribosomal subunit and protein synthetic activity. These data suggest that the activation of eIF-2B following fertilization reflects the fertilization-induced increase in NADPH levels.
authors.affiliation: Center of Marine Biotechnology, Baltimore, Maryland 21202.
authors.forename: G R
authors.initials: GR
authors.lastname: Akkaraju
authors.forename: L J
authors.initials: LJ
authors.lastname: Hansen
authors.forename: R
authors.initials: R
authors.lastname: Jagus
mesh_terms: D000818:Animals; D002474:Cell-Free System; D004625:Embryo, Nonmammalian / Q000378:metabolism; D005306:Fertilization; D005958:Glucosephosphates / Q000494:pharmacology; D020662:Guanine Nucleotide Exchange Factors; D009249:NADP / Q000378:metabolism; D010063:Ovum / Q000187:drug effects / Q000378:metabolism; D010084:Oxidation-Reduction; D014176:Protein Biosynthesis / Q000187:drug effects; D011506:Proteins / Q000378:metabolism*; D012617:Sea Urchins
chemical_list: D005958:Glucosephosphates; D020662:Guanine Nucleotide Exchange Factors; D011506:Proteins; D009249:NADP