Figure 2.
Cholesterol level increased in dnpc1a mutant brain. A, Total cholesterol content of dnpc1a mutant heads (dnpc1a1) is increased more than threefold compared with age-matched w1118 controls in the day 5 adult. Free cholesterol (black) and cholesterol esters (white) were measured separately in an enzymatic assay from head homogenates (n = 3). Significance is indicated at ***p < 0.001. B, Representative HPLC–MS/MS traces of cholesterol from isolated w1118 control and null dnpc1a brains (dnpc1a1) in the day 5 adult. Sterols from dissected brains were sulfated, resolved by HPLC, and identified in the presence of internal standard ([13C2]-cholesterol) by negative mode electrospray ionization MS/MS. The top two representative traces are from control brains, and the bottom two traces are from dnpc1a null brains. C, Quantification of HPLC–MS/MS measurements of cholesterol and ergosterol. Brains from dnpc1a mutants (open bars) have a more than twofold increase in cholesterol levels compared with controls (filled bars), whereas ergosterol levels are not significantly different. Significance is indicated as *p < 0.050.