FIGURE 2.

CGA codon repeats inhibit expression in a dose-dependent manner. (A) Luciferase activity of three different reporter constructs (X₄F, RX₃₁₄F, and X₄R), containing (Arg)₁₀ insertions specified by each of the six Arg codons. (B) The relationship between CGA codon dose and luciferase activity was examined with (Arg)₁₀ inserts containing increasing CGA content, as illustrated in the schematic. (C) Firefly luciferase activity as a function of CGA codon dose in X₄F (Δ) and RX₃₁₄F (▪)—reporter constructs. (D) Firefly luciferase activity of X₄F-reporter constructs containing either no insertion, or insertion of four Arg residues, specified with the indicated CGA or AGA codons. Values were normalized to the X₄F-(AGA)₄ reporter. (E) Expression of integrated GFP constructs with three Arg residues inserted at amino acid 4 specified by AGA or CGA codons. GFP expression was assessed based on the distribution of yeast cells exhibiting different intensities of fluorescence emission at 530 nm.