Hashimoto K, Sato N
Department of Molecular Biology, Faculty of Science, Saitama University, Saitama Prefecture, 338-8570, Urawa, Japan
Plant Sci. 2001 Apr;160(5):807-815. doi: 10.1016/s0168-9452(00)00444-1.
The nad7 gene, encoding the subunit 7 of NADH dehydrogenase complex I, is located in the mitochondrial genome in some species of green algae and seed plants, while it is nuclear-encoded in fungi and animals. In a liverwort, the presence of a mitochondrial nad7 pseudogene, and a nuclear nad7 gene has been reported. We have isolated the mitochondrial nad7 gene of the moss Physcomitrella patens. This gene is transcribed as a monocistronic mRNA and contains two group II introns that correspond to the first two of the four introns in the nad7 genes in angiosperms. Results of phylogenetic analysis supported monophyly of the nad7 genes of mosses and tracheophytes. Available data suggest that the nuclear transfer of the nad7 gene occurred only in the liverwort lineage, which diverged extensively from the mosses and tracheophytes with respect to the nad7 gene.
NAD7基因编码NADH脱氢酶复合体I的亚基7，在一些绿藻和种子植物物种中，它位于线粒体基因组中，而在真菌和动物中则由核基因编码。在一种地钱中，已报道存在线粒体nad7假基因和一个核nad7基因。我们分离出了小立碗藓的线粒体nad7基因。该基因转录为单顺反子mRNA，包含两个II类内含子，它们对应于被子植物nad7基因四个内含子中的前两个。系统发育分析结果支持苔藓植物和维管植物的nad7基因是单系的。现有数据表明，nad7基因的核转移仅发生在地钱谱系中，就nad7基因而言，地钱与苔藓植物和维管植物有很大差异。
