title: Two classes of translational control RNA: their role in the regulation of  protein synthesis.
abstract: Two classes of translation control RNA (tcRNA) have been isolated from embryonic chick muscle. One of these classes, the tcRNA isolated from messenger ribonucleoprotein particles (mRNP-tcRNA), is effective in inhibiting the translation of mRNP-mRNA while having little if any effect on polysomal mRNA. The other class, polysome-tcRNA, has no effect on mRNP-mRNA while it stimulates the translation of polysomal mRNA. The mRNP tcRNA contains approximately 50 percent uridylate residues and forms small but stable hybrids with poly (A), while polysome-tcRNA contains fewer uridylate residues and is much less effective in forming a hybrid with poly (A). A proposed model concerning the role of these two classes of tcRNA in the regulation of protein synthesis is presented.
mesh_terms: D000818:Animals; D001798:Blood Proteins / Q000096:biosynthesis*; D002499:Centrifugation, Density Gradient; D009693:Nucleic Acid Hybridization; D009698:Nucleoproteins / Q000378:metabolism; D011132:Polyribosomes / Q000378:metabolism; D014176:Protein Biosynthesis; D012313:RNA / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D012260:Ribonucleases; D012265:Ribonucleotides / Q000032:analysis
chemical_list: D001798:Blood Proteins; D009698:Nucleoproteins; D012333:RNA, Messenger; D012265:Ribonucleotides; D012313:RNA; D012260:Ribonucleases