Ribosomal frameshifting efficiency and gag/gag-pol ratio are critical for yeast M1 double-stranded RNA virus propagation

J D Dinman, R B Wickner
1992 Journal of Virology  
About 1.9%o of ribosomes translating the gag open reading frame of the yeast L-A double-stranded RNA virus positive strand undergo a -1 frameshift and continue translating in the pol open reading frame to make a 170-kDa gag-pol fusion protein. The importance of frameshifting efficiency for viral propagation was tested in a system where the Ml (killer toxin-encoding) satellite RNA is supported by a full-length L-A cDNA clone. Either increasing or decreasing the frameshift efficiency more than
more » ... ciency more than twofold by alterations in the slippery site disrupted viral propagation. A threefold increase caused by a chromosomal mutation, hshl (high shifter), had the same effect. Substituting a +1 ribosomal frameshift site from Tyl with the correct efficiency also allowed support of Ml propagation. The normal -1 frameshift efficiency is similar to the observed molar ratio in viral particles of the 170-kDa gag-pol protein to the 70-kDa gag gene product, the major coat protein. The results are interpreted in terms of a packaging model for L-A.
doi:10.1128/jvi.66.6.3669-3676.1992 fatcat:h5nwvwowdbcxbo37sig6godi2a