The unique features of the mitochondrial genome, such as its high copy number and lack of defined mechanisms of recombination, have hampered efforts to manipulate its sequence to create specific mutations in mouse mtDNA. As such, the generation of in vivo mouse models of mtDNA disease has proved technically challenging. This chapter describes a unique approach to create mitochondrial oxidative phosphorylation (OXPHOS) defects in mouse ES cells by transferring mtDNA from different murid species into Mus musculus domesticus ES cells using cytoplasmic hybrid ("cybrid") fusion. The resulting "xenocybrid" ES cells carry OXPHOS defects of varying severity, and can be utilized to generate live mouse models of mtDNA disease.
Keywords: Embryonic stem cell s; Fibroblasts; Fusion; Mouse; Xenocybrid.