Expression of a Set of Synthetic Suppressor tRNAPhe Genes in Saccharomyces cerevisiae

Synthetic ochre and amber tRNA suppressor genes derived from the yeast tRNAGAAPhe sequence have been constructed. They were efficiently transcribed in vitro and expressed in vivo via a synthetic expression cassette. tRNAUUAPhe and tRNAUUAPheΔ IVS (IVS = intervening sequence) are relatively inefficient ochre suppressors. They are toxic to the cell when expressed on a multicopy plasmid, and they do not suppress at all when present as single copies. The intron does not seem to have any effect on suppression. In contrast, the amber suppressor tRNACUAPheΔ IVS is efficient when expressed from a single-copy plasmid, while its efficiency is reduced on a multicopy vector.