FIGURE 3.

NR production contributes to enhanced NAD⁺ homeostasis in ssy5Δ cells. A, overall gene expression of the NAD⁺ biosynthetic pathway remains largely similar in ssy5Δ cells compared with WT. Results show relative gene expression (normalized to ACT1) determined by qPCR. B, deletion of SSY5 increases gene expression of the phosphate sensing (PHO) pathway components. Results show gene expression comparisons between WT and ssy5Δ cells. C, deletion of SSY5 rescues the short RLS of the NAD⁺ biosynthesis-deficient npt1Δ mutant (npt1Δ versus ssy5Δnpt1Δ; p < 0.005). D, deletion of SSY5 increases both NAD⁺ and NADH levels in npt1Δ cells. E, deletion of SSY5 increases intracellular NR levels in npt1Δ cells. Data shown are representative of multiple independent experiments. Error bars denote S.D. derived from triplicate samples. The p values were calculated using Student's t test (ns, not significant; *, p < 0.05; **, p < 0.01; ***, p < 0.005) except for C (Wilcoxon rank sum test).