Figure 1.

Improved Motor Function and Extended Lifespan in Ndufs4^−/−::Opa1^tg Double Mutants

(A) Rotarod analysis (n = 6/group). Dashed blue: WT; dashed red: Opa1^tg; solid blue: Ndufs4^−/−; solid red: Ndufs4^−/−::Opa1^tg. Error bars represent SEM. The asterisks represent the significance levels calculate by unpaired, two-tail Student’s t test, ^∗p < 0.05, ^∗∗∗p < 0.005, and refer to the comparison between Ndufs4^−/−::Opa1^tg and Ndufs4^−/−.

(B) Kaplan-Meier survival probability. Significance was assessed by the log rank test. Solid blue: Ndufs4^−/− (n = 16); solid red: Ndufs4^−/−::Opa1^tg (n = 9).

(C) Oxygen consumption measurements (nmol O₂/min/mg of protein). Solid blue: WT (n = 5); blue outline: Opa1^tg (n = 5); solid red: Ndufs4^−/− (n = 5); red outline: Ndufs4^−/−::Opa1^tg (n = 6). The asterisks represent the significance levels calculate by unpaired, two-tail Student’s t test ^∗p < 0.05.

(D) MRC activities (nmol/min/mg of protein) in isolated brain mitochondria. Solid blue: WT (n = 8); blue outline: Opa1^tg (n = 5); solid red: Ndufs4^−/− (n = 7); red outline: Ndufs4^−/−::Opa1^tg (n = 8). Error bars represent SEM. The asterisks represent the significance levels calculate by unpaired, two-tail Student’s t test ^∗p < 0.05.

(E) Western blot analysis of subunits from CI (NDUFA9 and NDUFB8), CII (SDHA), CIII (UQCRC2), CIV (COX1), and CV (ATP5A) in brain isolated mitochondria. VDAC is taken as an internal control.

(F) Electron microscopy of brain specimens from the different genotypes. Note that mitochondrial morphology is well preserved in Ndufs4^−/−::Opa1^tg versus Ndufs4^−/−. Scale bar 1 μm.