Extra copies of TEF5 manifest an antisuppressor effect in the strain with the ochre tRNA SUP4 suppressor. The strain 50V-H78 (SUP4), was transformed with one of the multicopy plasmids YEplac181-TEF5Δi (TEF5-Δi↑), YEplac181-TEF2 (TEF2↑), YEplac181-SUP35C (SUP35C↑) or YEplac181 (empty vector). The appropriate dual luciferase reporter plasmids were then introduced into cells of obtained transformants. The transformants with plasmid pairs were grown and readthrough measured as described in legend to Figure 3 and in Methods. The plasmids YEplac181-TEF5Δi and YEplac181-SUP35C cause a statistically significant (P ≤ 0.01 and P ≤ 0.002, respectively) decrease of UAA readthrough levels compared to those in transformants carrying YEplac181.