title: The origin of multiple polypeptides of molecular weight below 110 000 encoded by tobacco mosaic virus RNA in the messenger-dependent rabbit reticulocyte lysate.
abstract: Multiple polypeptides encoded by tobacco mosaic virus (TMV) RNA in the messenger-dependent rabbit reticulocyte lysate are not attributable to contaminating 3'-coterminal RNA fragments, multiple leaky termination codons or endonuclease activity opening-up legitimate or spurious internal initiation sites. Quantitative analysis of polypeptides encoded over a range of added RNA concentrations from 0.09 microgram X ml-1 to 180 micrograms X ml-1 compared with those synthesized in response to size-fractionated RNAs from a crude virus preparation, or with RNA extracted from the alkali-stable fraction of TMV suggest that apart from four legitimate virus-coded products of apparent Mr approx. 165 000, 110 000, 30 000 and 17 500 all other polypeptides arise from the overlapping 5'-proximal cistrons either by (i) site-selective endonucleolytic cleavage, (ii) sense codon misreading, or (iii) specific regions of secondary structure on TMV RNA which impede ribosome translocation.
mesh_terms: D000818:Animals; D002474:Cell-Free System; D007700:Kinetics; D008970:Molecular Weight; D010455:Peptides / Q000235:genetics* / Q000302:isolation & purification; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics*; D012367:RNA, Viral / Q000235:genetics*; D011817:Rabbits; D012156:Reticulocytes / Q000378:metabolism*; D014027:Tobacco Mosaic Virus / Q000235:genetics*; D014764:Viral Proteins / Q000235:genetics* / Q000302:isolation & purification
chemical_list: D010455:Peptides; D012333:RNA, Messenger; D012367:RNA, Viral; D014764:Viral Proteins