Generation and application of mtDNA knockout mice as models for mitochondrial diseases

具有致病性突变线粒体DNA （mtDNA）的小鼠将为研究突变mtDNA如何在组织中传播和分布从而导致线粒体疾病的表达提供理想的系统，但没有有效的程序可用于它们的产生。分离mtDNA-less （ρ^0）小鼠细胞使我们能够将积累在体细胞组织中的小鼠突变mtDNA捕获到mtDNA重新填充的ρ^0细胞（cybrids）中。我们可以分离出具有缺失突变mtDNA的呼吸缺陷杂交体，并将其引入受精卵。突变体mtDNA通过母系遗传，其积累导致多种组织的线粒体功能障碍。此外，这些小鼠中的大多数意外地死于肾功能衰竭，这表明mtDNA突变参与了新疾病的发病机制。通过广泛的间歇线粒体相互作用，可以使具有高达90%突变mtDNA的组织从疾病表型的表达中逃脱。

Mice possessing pathogenic mutant mitochondrial DNA (mtDNA) would provide ideal systems for studying exactly how mutant mtDNAs are transmitted and distributed in tissues resulting in expression of mitochondrial diseases, but no effective procedures are available for their generation. Isolation of mtDNA-less (ρ^0) mouse cells enabled us to trap mouse mutant mtDNAs that had accumulated in somatic tissues into mtDNA repopulated ρ^0 cells (cybrids). We could isolate respiration-deficient cybrids with a deletion mutant mtDNA and introduce it into fertilized eggs. The mutant mtDNA was transmitted maternally, and its accumulation induced mitochondrial dysfunction in various tissues. Moreover, most of these mice unexpectedly died as a consequence of renal failure, suggesting the involvement of mtDNA mutations in the pathogeneses of new diseases. Escape ofJhe tissues with up to 90 % mutant mtDNA from expression of disease phenotypes was enabled by the extensive intermitochondrial interaction.