Dynamic modulation of Dnmt2-dependent tRNA methylation by the micronutrient queuine.
Dynamic modulation of Dnmt2-dependent tRNA methylation by the micronutrient queuine.
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DOI：
10.1093/nar/gkv980
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发表时间：
2015-12-15
影响因子：
14.9
通讯作者：
Ehrenhofer-Murray AE
中科院分区：
文献类型：
--
作者：
Müller M;Hartmann M;Schuster I;Bender S;Thüring KL;Helm M;Katze JR;Nellen W;Lyko F;Ehrenhofer-Murray AE
Dnmt2酶是胞嘧啶-5甲基转移酶，可将几种trna的C38甲基化。我们在这里报道了两个Dnmt2同源物的活性，来自pombe Schizosaccharomyces的Pmt1和来自Dictyostelium disideum的DnmA，被底物tRNA的事先queuosine (Q)修饰强烈刺激。细胞在含队列培养基中生长可刺激体内tRNA甲基化水平；体外含q RNA增强Pmt1活性；队列刺激的体内甲基化由于缺乏将队列插入tRNA的酶（真核tRNA-鸟嘌呤转糖基化酶）而被取消。对S. pombe中tRNA甲基化的整体分析显示，Pmt1对tRNAAsp甲基化具有显著的选择性，这将Pmt1与其他Dnmt2同源物区分开来。本分析还揭示了S. pombe中tRNAPro的C34位点上一个新的与Pmt1和q无关的tRNA甲基化位点。值得注意的是，叶酸是一种微量营养素，可由饮食和肠道菌群中的高级真核生物清除。因此，这项工作揭示了一种意想不到的途径，通过这种途径，环境可以调节生物体中的tRNA修饰。
Dnmt2 enzymes are cytosine-5 methyltransferases that methylate C38 of several tRNAs. We report here that the activities of two Dnmt2 homologs, Pmt1 from Schizosaccharomyces pombe and DnmA from Dictyostelium discoideum, are strongly stimulated by prior queuosine (Q) modification of the substrate tRNA. In vivo tRNA methylation levels were stimulated by growth of cells in queuine-containing medium; in vitro Pmt1 activity was enhanced on Q-containing RNA; and queuine-stimulated in vivo methylation was abrogated by the absence of the enzyme that inserts queuine into tRNA, eukaryotic tRNA-guanine transglycosylase. Global analysis of tRNA methylation in S. pombe showed a striking selectivity of Pmt1 for tRNAAsp methylation, which distinguishes Pmt1 from other Dnmt2 homologs. The present analysis also revealed a novel Pmt1- and Q-independent tRNA methylation site in S. pombe, C34 of tRNAPro. Notably, queuine is a micronutrient that is scavenged by higher eukaryotes from the diet and gut microflora. This work therefore reveals an unanticipated route by which the environment can modulate tRNA modification in an organism.