title: Cytoplasmic nonpolysomal messenger ribonucleoprotein containing actin messenger RNA in chicken embryonic muscles.
abstract: Cytoplasmic nonpolysomal mRNAs have been isolated in the form of 16-40S ribonucleoprotein particles from the postribosomal supernatant of 14-day-old chick embryonic muscles. An 8-20S RNA fraction isolated from these particles directs the synthesis of actin in a wheat germ embryo S-30 system, as judged by copurification of the products with chicken muscle actin by repeated cycles of G- to F-actin transformation; mobilities of the purified product on sodium dodecyl sulfate-polyacrylamide gels and urea gels; and analysis of the CNBr-cleaved peptides. The 16-40S particles have a buoyant density of 1.4 g/cm3 which corresponds to an RNA/protein ratio of 1:3. They do not contain detectable levels of ribosomal subunits, as judged by the absence of typical ribosomal proteins in the range of 15,000-30,000. They contain at least eight distinct polypeptide species in the molecular weight range of 44,000-100,000, including a prominent 44,000 species. The presence of these particles suggests that they may have a role in the regulation of translation in developing muscles.
mesh_terms: D000199:Actins / Q000096:biosynthesis*; D049148:Aminoacylation; D000818:Animals; D002642:Chick Embryo; D008970:Molecular Weight; D009124:Muscle Proteins / Q000302:isolation & purification; D009132:Muscles / Q000032:analysis* / Q000378:metabolism; D009698:Nucleoproteins / Q000302:isolation & purification*; D010446:Peptide Fragments / Q000032:analysis; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000302:isolation & purification* / Q000378:metabolism; D012261:Ribonucleoproteins / Q000302:isolation & purification* / Q000378:metabolism; D012269:Ribosomal Proteins / Q000302:isolation & purification
chemical_list: D000199:Actins; D009124:Muscle Proteins; D009698:Nucleoproteins; D010446:Peptide Fragments; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D012269:Ribosomal Proteins