Mutations in SDH, but not LKR, induce mitochondrial abnormalities. (A) Schematic representation of full-length AASS-1 and the ok926 deletion mutant. LKR and SDH are indicated in green and blue, respectively. The wavy line represents the MTS. Point mutations are indicated with asterisks. The 10 frame-shifted amino acids generated by the ok926 deletion are indicated at the C terminus of the ok926 deletion mutant. (B) Representative images of Mito-GFP–labeled mitochondria in the hypodermis of N2 and aass-1 mutant animals. Bars, 5 µm. (C) Representative images of mitochondria in the hypodermis of control (ctrl) RNAi- and aass-1 RNAi-treated N2 and aass-1(yq170) animals. Bars, 5 µm. (D) Quantification of animals with abnormally enlarged mitochondria (area ≥12 µm²). 90 animals or more were scored for each genotype. (E–J) Images (E–I) and quantification (J) of the rescuing effects on aass-1(yq170) mitochondria of ectopically expressed MTS- and mCherry-fused LKR (MTS::LKR::mCh; E), SDH (MTS::SDH::mCh; F), SDH(S641F) (MTS::SDH(S641F)::mCh; G), SDH(G499E) (MTS::SDH(G499E)::mCh; H), and nonmitochondrion-targeted SDH::mCh (SDH::mCh; I). Bars, 5 µm. 90 animals or more were scored for each genotype (J). For all quantifications, *, P < 0.05; **, P < 0.01; and ***, P < 0.001. Error bars represent SEM.