Figure 6

Luciferase assay to measure read-through efficiency. Parental strain (WT) or rps9-Δ188 strain were transformed with a plasmid carrying the luciferase gene with a single premature stop codon ("Stop") or two consecutive stop codons ("2× stop"). Luciferase activity was measured after the induction of luciferase expression by 2 hr growth in medium containing galactose. A sample of cells carrying the premature stop codon was treated with paromomycin for 90 min to induce read-through efficiency. Note that the activity of a normal luciferase gene under these experimental conditions was at least 100 times higher than the single premature stop gene (data not shown).