FIGURE 8.

Expression of CNAP-tagged YLR290C preserves de novo Q biosynthesis. Levels of total ¹³C₆-Q₆ (¹³C₆-Q₆ + ¹³C₆-Q₆H₂) (A) and total ¹²C-Q₆ (¹²C-Q₆ + ¹²C-Q₆H₂) (B) were measured in the designated yeast strains by HPLC-MS/MS. Yeast strains were grown overnight in 5 ml of SD-complete, diluted to an A₆₀₀ of 0.05 in 50 ml of DOD-complete, labeled with either ¹³C₆-4HB or ¹³C₆-pABA at an A₆₀₀ of 0.5, and harvested after 3 h of labeling. Lipid measurements were normalized by the wet weight of extracted cells. Each bar represents the mean of four measurements from two biological samples with two injections each. Error bars represent standard deviations. Statistical significance was determined with the two-tailed Student's t test, and the lowercase letters above the bars are indicative of statistical significance. In A, the content of ¹³C₆-Q₆ in CA-1 and coq8Δ was compared with wild type with the corresponding ¹³C₆-labeled precursor; ¹³C₆-Q₆ synthesized by CA-1 was 70% of wild type and 80% of wild type with ¹³C₆-4HB and ¹³C₆-pABA, respectively (a, p = 0.0005; b, p = 0.0196). ND, not detected. In B, the content of ¹²C-Q₆ in CA-1 and coq8Δ was compared with wild type with the corresponding ¹³C₆-labeled precursor; accumulated ¹²C-Q₆ in CA-1 was 70% of wild type when labeled with either ¹³C₆-4HB or ¹³C₆-pABA (a, p = 0.0202; b, p = 0.0001). ND, not detected.