Comparison of relative mRNA levels (nonsense/sense). (A) The relative levels of LacZ mRNA in the wild-type, [PSI+], upf1Δ, and [PSI+]/upf1Δ strains expressed from the SXA reporters. (B) The relative levels of LacZ mRNA in the wild-type, [PSI+], upf1Δ, and [PSI+]/upf1Δ strains expressed from the QXQ reporters. (C) The relative levels of dual luciferase mRNA in the wild-type, [PSI+], upf1Δ, and [PSI+]/upf1Δ strains. (D) Representative Northern blot data from the wild-type and [PSI+]/upf1Δ strains expressing the β-galactosidase QXQ reporters. (E) Representative Northern blot data from the wild-type and [PSI+]/upf1Δ strains expressing the dual luciferase reporters. WT, wild type.