Expression of the wheat mitochondrial nad3-rps12 transcription unit: correlation between editing and mRNA maturation.
Expression of the wheat mitochondrial nad3-rps12 transcription unit: correlation between editing and mRNA maturation.
复制标题
小麦线粒体 nad3-rps12 转录单位的表达：编辑与 mRNA 成熟之间的相关性。
DOI：
--
复制
发表时间：
1991
期刊：
影响因子：
--
通讯作者：
J. Grienenberger
中科院分区：
文献类型：
--
作者：
J. Gualberto;G. Bonnard;L. Lamattina;J. Grienenberger
在植物线粒体中，RNA编辑涉及将基因组DNA中的胞苷转化为相应RNA中的尿苷。对线粒体RNAs反转录制备的cDNA的分析表明，小麦线粒体中存在部分编辑的RNAs。结合小麦线粒体基因座的表达，研究了这种部分编辑的程度及其对相应蛋白质序列的潜在影响。小麦线粒体转录单位含有四个开放阅读框(nad3、rps 12、orf299、orf156)的序列、表达和RNA编辑已被研究，它们都共转录成相同的主要前体RNA。Orf156的产物是一个功能未知的18kD的线粒体膜蛋白，而orf299的产物未被检测到，该序列可能是假基因。通过聚合酶链式反应技术获得的cDNA克隆的序列显示，除了与coxII基因的部分序列相同的序列外，nad3、rps12和orf156转录本被编辑，而orf299不被编辑。对从前体RNA获得的cDNA克隆的分析表明，存在大量部分编辑的nad3-rps12转录本，在编辑过程中没有明显的极性。这表明RNA编辑是一种转录后事件。此外，在前体、成熟转录本和多聚体转录本水平上的部分编辑研究表明，翻译主要使用成熟的、完全编辑的序列。在一些cDNA克隆中观察到编辑位点上的核苷酸缺失，这表明植物线粒体中的C-U RNA编辑可能是通过核苷酸替换来实现的。
In plant mitochondria, RNA editing involves the conversion of cytidines in the genomic DNA into uridines in the corresponding RNA. Analysis of cDNAs prepared by reverse transcription of mitochondrial RNAs has shown that partially edited RNAs are present in wheat mitochondria. The extent of this partial editing as well as its potential influence on the corresponding protein sequence were studied along with the expression of a wheat mitochondrial locus. The sequence, expression, and RNA editing of the wheat mitochondrial transcription unit containing four open reading frames (nad3, rps12, orf299, orf156), all cotranscribed into a same predominant precursor RNA, have been studied. The product of orf156 is an 18-kD mitochondrial membrane protein of unknown function, whereas the product of orf299 could not be detected and this sequence seems to be a pseudogene. Sequences of cDNA clones derived by the polymerase chain reaction technique show that nad3, rps12, and orf156 transcripts are edited, whereas orf299 is not edited, except for a sequence identical to part of the coxII gene. Analysis of cDNA clones obtained from the precursor RNA shows the presence of a large number of partially edited nad3-rps12 transcripts with no evident polarity for the editing process. This shows that RNA editing is a post-transcriptional event. In addition, study of partial editing at the level of precursor, mature, and polysomal transcripts shows that mainly mature, completely edited sequences are used for translation. Deletions of a nucleotide at editing sites were observed in a number of cDNA clones, suggesting that C----U RNA editing in plant mitochondria would be achieved by nucleotide replacement.