Control of translation efficiency in yeast by codon–anticodon interactions

Suppression of CGA-mediated expression defects by an exact base-pairing anticodon mutated tRNA^Arg(UCG). (A) Effect of indicated native and anticodon-mutated tRNA^Arg species, expressed on high copy plasmids, on firefly luciferase activity of X₄F-reporter constructs containing (CGA)₁₀ insertions. The parent tRNA of each anticodon-mutated tRNA^Arg is indicated by the first anticodon shown below the figure. Values were compared to activity of X₄F-(AGA)₁₀ luciferase in a strain with an empty vector. (B) Effect of an anticodon-mutated tRNA^Arg species, expressed on a high copy plasmid, on firefly luciferase activity of a RX₃₁₄F-reporter construct containing a (CGA)₁₀ insertion. (C) Suppression of the inhibitory effects of CGA codons by integrated copies of the mutant tRNA^Arg(UCG) species that decode CGA without wobble. Luciferase activity of X₄F-reporter constructs containing (Arg)₁₀ insertions, specified by (AGA)₁₀, [(CGA)₅(AGA)₅], or (CGA)₁₀, in yeast strains bearing an integrated copy of either of two native tRNA^Arg species, two nonnatural exact match tRNA^Arg species, or a vector control as indicated. Two individual integrant strains were analyzed in each case. Values were normalized to the average of the activity of X₄F-(AGA)₁₀ luciferase in the two integrant strains expressing a vector control. Error bars represent the standard deviation from three independent transformants, each assayed in triplicate. (D) A closer examination of expression of X₄F-reporter constructs containing (CGA)₁₀ insertions in indicated strains with an expanded scale of the y-axis. Values are normalized as in C.