title: A model of translational control involving mRNA-associated proteins in chick embryonic muscles.
abstract: Highly purified poly(A)-containing free and polysomal mRNP particles have been isolated by chromatography of subcellular fractions of chick embryonic muscles on oligo-dT-cellulose and elution with low salt buffer at 45 degrees. The free and polysomal mRNP represent two distinct classes of macromolecules, the free particles having a more complex nucleoprotein organization than the polysomal particles. Comparison of the protein moieties of three classes of poly(A)-containing cytoplasmic mRNP -- those released from nuclei after in vitro transcription and processing (transported mRNP), the free, and polysomal mRNP -- strongly suggests that the majority of the mRNA-associated proteins are exchanged in the cytoplasm during the various functional states of mRNA. A model of translational control involving the participation of mRNA-associated proteins in chick embryonic muscles and by analogy in other differentiated eukaryotic cells is proposed.
mesh_terms: D000818:Animals; D002642:Chick Embryo; D008970:Molecular Weight; D009132:Muscles / Q000378:metabolism*; D009698:Nucleoproteins / Q000378:metabolism*; D011061:Poly A / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000302:isolation & purification / Q000378:metabolism*; D012261:Ribonucleoproteins / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D009698:Nucleoproteins; D012333:RNA, Messenger; D012261:Ribonucleoproteins; D011061:Poly A