Yoneda M, Miyatake T, Attardi G
Division of Biology, California Institute of Technology, Pasadena, USA.
Muscle Nerve Suppl. 1995;3:S95-101. doi: 10.1002/mus.880181420.
The heteroplasmic tRNA(Lys) mutation in the mitochondrial DNA (mtDNA) is responsible for the phenotypic expression and the transmission of MERRF syndrome. However, the genetic behaviors of the mutant and wild-type mtDNA molecules within a cell are still unknown. We demonstrated a clear genetic complementation of the mutant and wild-type mtDNAs, with a sharp threshold around 10% in the wild-type, in the MERRF transformants, and in their subclones by a cytoplast transfer of the mitochondria into an mtDNA-less cell line, rho o cell. By contrast, no interaction was observed between the two functionally complementary mtDNAs that were originally located in distinct organelles and sequentially introduced into a rho o cell line (genetic independence). These results imply that the sorting of the mtDNA molecules among mitochondria plays a crucial role in the phenotypic expression and transmission of the disease.
线粒体DNA（mtDNA）中的异质性tRNA（Lys）突变是肌阵挛性癫痫伴破碎红纤维综合征（MERRF）表型表达和遗传传递的原因。然而，细胞内突变型和野生型mtDNA分子的遗传行为仍不清楚。通过将线粒体的细胞质体转移到无mtDNA的细胞系ρ0细胞中，我们在MERRF转化体及其亚克隆中证明了突变型和野生型mtDNA之间存在明显的遗传互补，野生型的阈值约为10%。相比之下，最初位于不同细胞器中并依次引入ρ0细胞系的两个功能互补的mtDNA之间未观察到相互作用（遗传独立性）。这些结果表明，mtDNA分子在线粒体之间的分选在该疾病的表型表达和遗传传递中起关键作用。
