Hiesel R, Wissinger B, Schuster W, Brennicke A
Institut für Genbiologische Forschung, Berlin, Federal Republic of Germany.
Science. 1989 Dec 22;246(4937):1632-4. doi: 10.1126/science.2480644.
Comparative sequence analysis of genomic and complementary DNA clones from several mitochondrial genes in the higher plant Oenothera revealed nucleotide sequence divergences between the genomic and the messenger RNA-derived sequences. These sequence alterations could be most easily explained by specific post-transcriptional nucleotide modifications. Most of the nucleotide exchanges in coding regions lead to altered codons in the mRNA that specify amino acids better conserved in evolution than those encoded by the genomic DNA. Several instances show that the genomic arginine codon CGG is edited in the mRNA to the tryptophan codon TGG in amino acid positions that are highly conserved as tryptophan in the homologous proteins of other species. This editing suggests that the standard genetic code is used in plant mitochondria and resolves the frequent coincidence of CGG codons and tryptophan in different plant species. The apparently frequent and non-species-specific equivalency of CGG and TGG codons in particular suggests that RNA editing is a common feature of all higher plant mitochondria.
对高等植物月见草中几个线粒体基因的基因组克隆和互补DNA克隆进行的比较序列分析揭示了基因组序列与信使RNA衍生序列之间的核苷酸序列差异。这些序列改变最容易通过特定的转录后核苷酸修饰来解释。编码区的大多数核苷酸交换导致mRNA中的密码子改变，这些密码子所指定的氨基酸在进化中比基因组DNA编码的氨基酸更保守。有几个例子表明，基因组中的精氨酸密码子CGG在mRNA中被编辑为色氨酸密码子TGG，这些氨基酸位置在其他物种的同源蛋白质中作为色氨酸高度保守。这种编辑表明植物线粒体中使用的是标准遗传密码，并解决了不同植物物种中CGG密码子与色氨酸频繁重合的问题。特别是CGG和TGG密码子明显频繁且非物种特异性的等效性表明，RNA编辑是所有高等植物线粒体的一个共同特征。
