Kadowaki K, Kubo N, Ozawa K, Hirai A
National Institute of Agrobiological Resources, Department of Molecular Biology, Tsukuba, Ibaraki, Japan.
EMBO J. 1996 Dec 2;15(23):6652-61.
We have cloned a gene for mitochondrial ribosomal protein S11 (RPS11), which is encoded in lower plants by the mitochondrial genome, in higher plants by the nuclear genome, demonstrating genetic information transfer from the mitochondrial genome to the nucleus during flowering plant evolution. The sequence s11-1 encodes an N-terminal extension as well as an organelle-derived RPS11 region. Surprisingly, the N-terminal region has high amino acid sequence similarity with the presequence of the beta-subunit of ATP synthase from plant mitochondria, suggesting a common lineage of the presequences. The deduced N-terminal region of s11-2, a second nuclear-encoded homolog of rps11, shows high sequence similarity with the putative presequence of cytochrome oxidase subunit Vb. The sharing of the N-terminal region together with its 5' flanking untranslated nucleotide sequence in different proteins strongly suggests an involvement of duplication/recombination for targeting signal acquisition after gene migration. A remnant of ancestral rps11 sequence, transcribed and subjected to RNA editing, is found in the mitochondrial genome, indicating that inactivation of mitochondrial rps11 gene expression was initiated at the translational level prior to termination of transcription.
我们克隆了线粒体核糖体蛋白S11（RPS11）的一个基因，该基因在低等植物中由线粒体基因组编码，在高等植物中由核基因组编码，这表明在开花植物进化过程中存在从线粒体基因组到核基因组的遗传信息转移。序列s11-1编码一个N端延伸以及一个源自细胞器的RPS11区域。令人惊讶的是，N端区域与植物线粒体ATP合酶β亚基的前序列具有高度的氨基酸序列相似性，这表明前序列有共同的起源。rps11的第二个核编码同源物s11-2的推导N端区域与细胞色素氧化酶亚基Vb的推定前序列显示出高度的序列相似性。不同蛋白质中N端区域及其5'侧翼非翻译核苷酸序列的共享强烈表明，基因迁移后通过重复/重组参与了靶向信号的获取。在线粒体基因组中发现了祖先rps11序列的残余部分，该部分被转录并进行RNA编辑，这表明线粒体rps11基因表达的失活在转录终止之前就已在翻译水平上开始。
