Wilson R K, Hanson M R
Section of Genetics and Development, Cornell University, Biotechnology Building, Ithaca, NY 14853, USA.
Curr Genet. 1996 Dec;30(6):502-8. doi: 10.1007/s002940050162.
Transcripts of most plant mitochondrial protein-coding genes exhibit C-to-U RNA editing events. In Petunia, two co-transcribed genes, nad3 and rps12, exhibit transcripts which are not fully edited at all potential editing sites. We investigated the nad3/rps12 transcript population in four different genotypes. In one pair of genotypes, the nuclear genome is identical but the nad3/rps12 genes are in different transcriptional contexts. Both the nad3/ rps12 genes and the plant mitochondrial genomes are identical in a second pair of genotypes, but the nuclear background is derived from two different Petunia species. We found that the overall extent of editing varied greatly between genotypes and is affected by nuclear genotype but not by the global transcriptional context. Local sequence context around a particular site does affect editing frequency. In all genotypes, certain sites exhibit high editing frequency, but these sites do not share obvious primary sequence characteristics. In all genotypes examined, editing sites which do not affect the encoded amino acid are less frequently edited than sites which alter codons to non-synonymous forms. All these data indicate that an unidentified property of the sequences immediately surrounding a cytosine affect its selection as a target in the editing process.
大多数植物线粒体蛋白质编码基因的转录本都存在C到U的RNA编辑事件。在矮牵牛中，两个共同转录的基因nad3和rps12，其转录本在所有潜在编辑位点都未被完全编辑。我们研究了四种不同基因型中的nad3/rps12转录本群体。在一对基因型中，核基因组相同，但nad3/rps12基因处于不同的转录环境。在第二对基因型中，nad3/rps12基因和植物线粒体基因组都相同，但核背景来自两个不同的矮牵牛物种。我们发现，编辑的总体程度在不同基因型之间差异很大，并且受核基因型影响，但不受整体转录环境影响。特定位点周围的局部序列环境确实会影响编辑频率。在所有基因型中，某些位点表现出高编辑频率，但这些位点没有明显的一级序列特征。在所有检测的基因型中，不影响编码氨基酸的编辑位点比将密码子改变为非同义形式的位点编辑频率更低。所有这些数据表明，紧邻胞嘧啶的序列的一个未确定特性会影响其在编辑过程中作为靶点的选择。
