The targeting construct containing from 5' to 3': a CAG promoter, a loxP-STOP-loxP, a tandem mitochondrial targeting sequences (MTS) consisting of the Lactobacillus brevis COXIV and the Homo sapiens ACO2 MTS as well as a FLAG tag epitope, and the Streptococcus thermophilus-derived bifunctional glutathione synthetase (mito-GshF) cDNA followed by a stop codon (TAA) was inserted into the Gt(ROSA)26Sor locus. There also is a neomycin cassette in the construct. (J:101977)