Yokobori S, Pääbo S
Institute of Zoology, University of Munich, Germany.
Proc Natl Acad Sci U S A. 1995 Oct 24;92(22):10432-5. doi: 10.1073/pnas.92.22.10432.
Some mitochondrial tRNA genes of land snails show mismatches in the acceptor stems predicted from their gene sequences. The majority of these mismatches fall in regions where the tRNA genes overlap with adjacent downstream genes. We have synthesized cDNA from four circularized tRNAs and determined the sequences of the 5' and 3' parts of their acceptor stems. Three of the four tRNAs differ from their corresponding genes at a total of 13 positions, which all fall in the 3' part of the acceptor stems as well as the discriminator bases. The editing events detected involve changes from cytidine, thymidine, and guanosine to adenosine residues, which generally restore base-pairing in the stems. However, in one case an A-A mismatch is created from an A-C mismatch. It is suggested that this form of RNA editing may involve polyadenylylation of the maturing tRNAs as an intermediate.
陆地蜗牛的一些线粒体tRNA基因在根据其基因序列预测的接受茎中存在错配。这些错配大多位于tRNA基因与相邻下游基因重叠的区域。我们从四个环化的tRNA合成了cDNA，并确定了其接受茎5'和3'部分的序列。四个tRNA中的三个在总共13个位置与其相应基因不同，这些位置都位于接受茎的3'部分以及判别碱基。检测到的编辑事件涉及胞嘧啶、胸腺嘧啶和鸟苷向腺苷残基的变化，这通常会恢复茎中的碱基配对。然而，在一种情况下，A-C错配会产生A-A错配。有人认为，这种RNA编辑形式可能涉及成熟tRNA的聚腺苷酸化作为中间步骤。
