CI was almost disappeared in Fars2 knockdown neurons after 16 days in culture, whereas CII and CV were slightly increased following 4 and 16 days of infection respectively (Fig. 5G and H); and the ND1 level showed significantly reduction in Fars2 knockdown neurons at 16th day but can still be synthesized, which indicate that fars2 knocking down affect both ND1 translation process and the assembly of mitochondrial CI in neurons (Fig. 5I and J). The gene discussed is FARS2; the disease is infection.