Mol Biol Evol. 2010 Jan;27(1):7-10. doi: 10.1093/molbev/msp223.
Many genes inherited from the alpha-proteobacterial ancestor of mitochondria have undergone evolutionary transfer to the nuclear genome in eukaryotes. In some rare cases, genes have been functionally transferred in pieces, resulting in split proteins that presumably interact in trans within mitochondria, fulfilling the same role as the ancestral, intact protein. We describe a nucleus-encoded mitochondrial protein (here named Cox1-c) in the amoeboid protist Acanthamoeba castellanii that is homologous to the C-terminal portion of conventional mitochondrial Cox1, whereas the corresponding portion of the mitochondrion-encoded A. castellanii Cox1 is absent. Bioinformatics searches retrieved nucleus-encoded Cox1-c homologs in most major eukaryotic supergroups; in these cases, also, the mitochondrion-encoded Cox1 lacks the corresponding C-terminal motif. These data constitute the first report of functional relocation of a portion of cox1 to the nucleus. This transfer event was likely ancient, with the resulting nuclear cox1-c being differentially activated across the eukaryotic domain.
许多从线粒体α-变形菌祖先遗传下来的基因在真核生物中经历了进化转移到核基因组。在某些罕见的情况下，基因被功能上分割成片段，导致分裂的蛋白质，推测在跨线粒体中相互作用，履行与祖先完整蛋白质相同的作用。我们描述了变形虫原生动物嗜热四膜虫中的一种核编码线粒体蛋白（此处命名为 Cox1-c），它与传统线粒体 Cox1 的 C 末端部分同源，而线粒体编码的嗜热四膜虫 Cox1 的相应部分缺失。生物信息学搜索在大多数主要的真核超群中检索到了核编码 Cox1-c 的同源物；在这些情况下，线粒体编码的 Cox1 也缺乏相应的 C 末端基序。这些数据首次报道了一部分 cox1 功能转移到细胞核。这种转移事件可能很古老，导致核 cox1-c 在真核域中被差异化激活。
