Gruska I, Jekabsons W, Schuster W
Institut für Genbiologische Forschung, Berlin, Germany.
Mol Gen Genet. 1995 Jun 10;247(5):529-36. doi: 10.1007/BF00290343.
We have characterized a mitochondrial gene in Oenothera, designated orf454, capable of encoding a component of the cytochrome c biogenesis system. This open reading frame is interrupted by an intron of 941 nucleotides showing high similarity to a group II intron residing in the rpl2 gene. RNA editing, which is observed at 18 cytidine positions within the orf454 reading frame, improves the similarity to protein-coding sequences in bacteria and higher plants and removes the last 16 amino acids. orf454 also shows high sequence similarity to two overlapping reading frames (orf169 and orf322) of Marchantia mitochondria. These ORFs belong to an operon-like cluster of genes in the liverwort that is not conserved in Oenothera mitochondria. However, in bacteria these reading frames are organized like the Marchantia gene cluster. It has been shown by genetical analysis in Rhodobacter capsulatus that these genes are essential for cytochrome c biogenesis. Genes of bacterial operons-ccl1 in Rhodobacter and yejR and nrfE in Escherichia coli - show high sequence similarity to the mitochondrial reading frames orf577 and orf454 of Oenothera. orf454, which we describe here, is homologous to the C-terminal region of these bacterial genes, while the previously described orf577 is homologous to the N-terminal region.
我们已经鉴定了月见草属中的一个线粒体基因，命名为orf454，它能够编码细胞色素c生物合成系统的一个组分。这个开放阅读框被一个941个核苷酸的内含子打断，该内含子与存在于rpl2基因中的II类内含子具有高度相似性。在orf454阅读框内的18个胞嘧啶位置观察到RNA编辑，这提高了与细菌和高等植物中蛋白质编码序列的相似性，并去除了最后16个氨基酸。orf454与地钱属线粒体的两个重叠阅读框（orf169和orf322）也显示出高度的序列相似性。这些开放阅读框属于地钱属中一个类似操纵子的基因簇，在月见草属线粒体中并不保守。然而，在细菌中，这些阅读框的组织方式与地钱属基因簇相似。在荚膜红细菌中的遗传学分析表明，这些基因对于细胞色素c生物合成是必不可少的。细菌操纵子的基因——红细菌中的ccl1以及大肠杆菌中的yejR和nrfE——与月见草属的线粒体阅读框orf577和orf454显示出高度的序列相似性。我们在此描述的orf454与这些细菌基因的C端区域同源，而先前描述的orf577与N端区域同源。
