In vitro Translation of Natural and Synthetic Beet Necrotic Yellow Vein Virus RNA-I

The in vitro translation of beet necrotic yellow vein virus RNA-1 was investigated in rabbit reticulocyte lysate and in wheatgerm extract using as messenger either RNA extracted from virions or a synthetic RNA-1 produced by in vitro transcription of full-length cDNA. In wheatgerm extract, RNA-1 directed the synthesis of approximately equivalent amounts of two long polypeptides of approximate Mr 220000 (220K) and 240K. The size of the translation products of Y-truncated RNA-1 transcripts suggested that synthesis of the 240K translation product was initiated at an AUG near the 5' terminus, probably AUG(154), the first initiation codon in the RNA-1 sequence. The 220K polypeptide is initiated internally, at AUG(496). In rabbit reticulocyte lysate only the internal initiation codon, AUG(496), was used for initiation on full-length RNA-1 although AUG(154) was accessible o'n short T-truncated transcripts