title: Ribosomes from Xenopus laevis eggs and embryos in a cell-free protein-synthesizing system: translational regulation.
abstract: Three types of ribosomal preparations from Xenopus laevis eggs and embryos were tested in a cell-free system to study possible translational regulation of protein synthesis as mediated by the ribosome during early amphibian development: type 1, a crude high-speed sediment, mainly containing monoribosomes completely dissociable by 0.5 M KC1; type II, ribosomes washed with 0.5 M KC1; and type III, ribosomes treated with puromycin - 0.5 M KC1. All three types showed an active response to the addition of poly[U]. Type III was found to be the most active: levels of incorporation of 30 phenylalanine residues/ribosome were reached. In all three cases ribosomes prepared from unfertilized eggs were 30-40% less active in vitro than those from cleavage and gastrula stages.
mesh_terms: D000818:Animals; D002701:Chloramphenicol / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D005260:Female; D010063:Ovum / Q000378:metabolism* / Q000648:ultrastructure; D010649:Phenylalanine / Q000378:metabolism; D014176:Protein Biosynthesis; D012343:RNA, Transfer / Q000378:metabolism; D012270:Ribosomes / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism; D014981:Xenopus; D015053:Zygote / Q000378:metabolism* / Q000648:ultrastructure
chemical_list: D010649:Phenylalanine; D002701:Chloramphenicol; D012343:RNA, Transfer; D003513:Cycloheximide