Inactivation of genes required for mitochondrial β-ketoglutarate generation suppresses saccharopine accumulation and mitochondrial defects in aass-1(yq170) mutants. (A and B) Images (A) and quantification (B) of mitochondria in the hypodermis of N2, aass-1(yq170), slc-25A18.1(yq274), gdh-1(yq275), idh-2(ok3184), aass-1(yq170);slc-25A18.1(yq274), aass-1(yq170);gdh-1(yq275), and aass-1(yq170);idh-2(ok3184) animals. 90 animals or more were scored for each genotype. Bars, 5 µm. (C) TEM images of mitochondria in hypodermal cells in aass-1(yq170);slc-25A18.1(yq274), aass-1(yq170);gdh-1(yq275), and aass-1(yq170);idh-2(ok3184) double mutants. Boxed regions showing crista structures are magnified (3×) and shown in the bottom left corner in each image. Bars, 1 µm. (D and E) Relative levels of saccharopine (D) and lysine (E) in N2, aass-1(yq170), aass-1(yq170);slc-25A18.1(yq274), aass-1(yq170);gdh-1(yq275), and aass-1(yq170);idh-2(ok3184) animals. Data (mean ± SEM) are from three independent experiments as shown in Fig. S2 and are normalized to saccharopine or lysine levels in N2 animals. (F) Relative levels of α-ketoglutarate (α-KG) in N2, aass-1(yq170), aass-1(yq170);slc-25A18.1(yq274), aass-1(yq170);gdh-1(yq275), and aass-1(yq170);idh-2(ok3184) animals. Data (mean ± SEM) are from three independent experiments and are normalized to α-ketoglutarate levels in N2 animals. (G) Relative ATP levels in the hypodermis of animals with the indicated genotypes. Data (mean ± SEM) are from three independent experiments and are normalized to the ATP level in N2 animals. (H) Analysis of body lengths of adult animals (day 5 of adulthood) with the indicated genotypes. 10 synchronized animals were analyzed for each genotype. (I) Graphic summary of the metabolic pathways involved in lysine catabolism and of the mitochondrial damage induced by saccharopine accumulation. For all quantifications, *, P < 0.05; **, P < 0.01; and ***, P < 0.001. Error bars represent SEM.