Studies on pathogenesis and gene therapy using mice with the mutated mtDNA in tRNA genes

(1)佐藤，A.等人。程序娜塔莉。阿卡德。SCI。美国：16765-16770。2005年，线粒体致病突变被证明与呼吸缺陷的表达和线粒体疾病的表达有关。这项研究直接解决了利用跨线粒体小鼠受精卵核移植对线粒体疾病进行基因治疗的问题。MITO小鼠表现出呼吸缺陷和线粒体疾病，这是由于携带大规模缺失的线粒体DNA(Δ线粒体DNA)积累所致。取第二极体作为活检标本，用于诊断有丝分裂小鼠受精卵的mtDNA基因分型。从有丝分裂小鼠的受精卵到去核的正常受精卵进行了核移植，结果表明，所有的F0后代终生都没有表现出呼吸缺陷。这一程序应适用于线粒体疾病的患者，以防止他们的孩子疾病。(2)佐藤，A。程序娜塔莉。阿卡德。SCI。…更多美国电话102：6057-6062。2005关于重组线粒体DNA是否在哺乳动物细胞中产生的问题，多年来一直存在争议。我们通过分离人类体细胞杂交细胞和产生携带两种不同mtDNA单倍型的小鼠，展示了非常罕见的重组mtDNA单倍型创建的令人信服的证据。线粒体DNA重组的频率如此之低，不需要对基于其缺失的关于人类进化的重要概念进行任何修改。(3)Liqin，C.等人。大自然的吉内特。39：386-390,2007线粒体DNA变异在世代之间快速转移的观察开创了瓶颈理论。长期以来一直被提出的一个流行的假说是，在卵子发生的早期，线粒体DNA含量的大量减少导致了瓶颈。为了验证这一点，我们估计mtDNA拷贝单个在发育阶段表现出一致和适度的mtDNA拷贝数，而初级卵母细胞在卵母细胞成熟早期表现出大量的mtDNA扩张。有些体细胞的线粒体DNA拷贝数很低。我们还证明了PGCs的每个细胞有100多个线粒体。综上所述，我们得出的结论是，线粒体瓶颈的产生并不是由于mtDNA拷贝数在卵子发生早期急剧下降，而是因为小鼠生殖细胞中mtDNA的有效分离单位数量较少。一些体细胞系在早期分化过程中有一个狭窄的瓶颈。这些结果为建立线粒体DNA分离模型和了解线粒体DNA疾病的复发风险提供了新的信息。较少

(1) Sato, A. et al. Proc. Natl. Acad. Sci. USA 102: 16765-16770. 2005Pathogenic mutations in mtDNAs have been shown to be responsible for expression of respiration defects and resultant expression of mitochondrial diseases. This study directly addressed the issue of gene therapy of mitochondrial diseases using nuclear transplantation of zygotes of trans-mitochondria mice (mito-mice). Mito-mice expressed respiration defects and mitochondrial diseases due to accumulation of mtDNA carrying a large-scale deletion (ΔmtDNA). Second polar bodies were used as biopsy samples for diagnosis of mtDNA genotypes of mito-mouse zygotes. Nuclear transplantation was carried out from mito-mouse zygotes to enucleated normal zygotes, and was shown to rescue all the F_0 progenies from expression of respiration defects throughout their lives. This -procedure should be applicable to patients with mitochondrial diseases for preventing their children from the diseases.(2) Sato, A. et al. Proc. Natl. Acad. Sci. … More USA 102: 6057-6062. 2005The problem of whether recombinant mtDNAs are created in mammalian cells has been controversial for many years. We show convincing evidence for the very rare creation of recombinant mtDNA haplotypes by isolating human somatic hybrid cells and by generating mice carrying two different mtDNA haplotypes. Such an extremely low frequency of mtDNA recombination does not require any revision of important concepts on human evolution that are based on its absence.(3) Liqin, C., et al. Nature Genet. 39:386-390, 2007The observations of rapid shifts in mtDNA variants between generations have originated the bottleneck theory. A prevalent hypothesis which has long been proposed is that a massive reduction in mtDNA content during early oogenesis leads to the bottleneck. To test this we estimated the mtDNA copy single exhibited consistent and moderate mtDNA copy numbers across developmental stages, while primary oocytes demonstrated substantial mtDNA expansion during early oocyte maturation. Some somatic cells possess a very low mtDNA copy number. We also demonstrated that PGCs have more than 100 mitochondria per cell. Taken together, we conclude that the mitochondrial bottleneck is not generated due to a mtDNA copy number drastic decline in early oogenesis rather to a small effective number of segregation units for mtDNA in mouse germ cells. Some somatic cell lineages have a narrow bottleneck during early differentiation. These results provide new information for generating mtDNA segregation models and for understanding of recurrence risks for mtDNA diseases. Less