TRANSLATION AND STRUCTURE OF THE RNAs OF BROME MOSAIC VIRUS

The four RNAs of the multicomponent Brome Mosaic Virus have been translated in wheat embryo cell-free extracts in order to characterize their cistrons. RNAs 1 and 2 are monocistronic; they each direct the synthesis of a single large polypeptide. RNA 3 is dicistronic but only one of its cistrons is translated. RNA 4 is a monocistronic messenger for the coat protein. The 5′ end of RNA 4 begins with m 7 G and a short sequence of A's and U's; these are followed by the initiation codon and codons for the amino acids of the coat protein. RNAs 1, 2 and 3 also have m 7 G at their 5′ terminus. The 3′ region of all four RNAs is remarkably similar in sequence.