Figure 3. Overexpression of DGAT2 but not PNPLA1 causes an increase in TG levels.
(a) HEK 293T cells transfected with plasmids encoding the indicated genes were labelled with [14C]linoleic acid for 4 h at 37 °C. Lipids were extracted, separated by normal-phase TLC and detected by autoradiography. 18:2 FA, linoleic acid; AcylCer, acylceramide. Four independent experiments gave similar results, and a representative result is shown. (b) HEK 293T cells were transfected with an empty vector or the plasmid encoding 3xFLAG-PNPLA1 or 3xFLAG-DGAT2. Twenty-four hours after transfection, lipids were extracted and subjected to LC-MS/MS analysis. TGs containing linoleic acid were detected by MRM mode and quantified using MassLynx software. The graph depicts the amount of each TG species containing linoleic acid (18:2) and FAs with the indicated chain-length and degree of unsaturation. For example, 30:1 means that the sum of chain-length and degree of unsaturation of the two FA chains other than linoleic acid are 30 and 1, respectively. Values represent the means±s.d.s of six (for control) or three (for PNPLA1 and DGAT2) independent experiments. Statistically significant differences compared to control cells are indicated (two-tailed Student's t-test; **P<0.01).