Figure 6

NQM1 Expression and growth phenotypes of NQM1/VHR1 mutants under oxidative stress. A) NQM1 mRNA expression in response to treatment with the oxidant menadione. Wild type and Δvhr1 mutant yeast induced NQM1 expression over time. B) H₂O₂ induces NQM1 in both wild type and Δvhr1 mutant; qRT-PCR was conducted on cells grown in liquid media containing glucose (2%) as sole carbon source. Oxidants were added to induce oxidative stress at mid-log growth phase (OD₆₀₀ = 0.8–1.0). C) Oxidant tolerance spot tests on media containing different concentrations of the oxidant menadione, H₂O₂ and diamide. Δvhr1 and Δvhr1/Δnqm1 mutants exhibit increased tolerance to menadione, Δnqm1 to H₂O₂, whereas the double mutants Δvhr1/Δtal1, Δnqm1/Δtal1 and the triple mutant Δvhr1/Δnqm1/Δtal1 were sensitive to this oxidant. Δvhr1 and Δvhr1/Δnqm1 mutants were sensitive to diamide, while all Δtal1 mutants were resistant to this oxidant.