CONVERSION OF MAMMALIAN TRANSFER-RNA 3' PROCESSING ENDORIBONUCLEASE TO 4-BASE-RECOGNIZING RNA CUTTERS
CONVERSION OF MAMMALIAN TRANSFER-RNA 3' PROCESSING ENDORIBONUCLEASE TO 4-BASE-RECOGNIZING RNA CUTTERS
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DOI：
10.1093/nar/23.18.3642
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发表时间：
1995-09-25
影响因子：
14.9
通讯作者：
NASHIMOTO, M
中科院分区：
文献类型：
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作者：
NASHIMOTO, M
哺乳动物细胞提取物中依赖于亚精胺的序列特异性核糖核酸内切酶（RNase 65）活性需要蛋白质和3'截短的tRNA，这两种物质指导它们的底物序列特异性。通过计算机分析寻找底物RNA与相应3'截短tRNA之间可能的碱基配对，提出了底物识别机制的统一模型，即靶tRNA切割位点上游1nt处的4个核苷酸序列与相应3'截短tRNA的5'端4个核苷酸序列之间存在碱基配对。在该模型中，tRNA底物与其相应的3'截短的tRNA形成类似于含有3'尾部的5'加工tRNA前体的复合物，表明RNase 65的蛋白组分与tRNA 3'加工核糖核酸内切酶相同从猪肝中纯化的3 'tRNase实际上只有在相应的3'截短的tRNA存在下才能在预期的位点切割靶RNA。这些结果表明3' tRNase可以被3'截短的tRNA转化为4nt特异性的RNA切割物。
The spermidine-dependent, sequence-specific endoribonuclease (RNase 65) activities in mammalian cell extracts require both protein and 3' truncated tRNA, species of which direct their substrate sequence specificity. Computer analysis for searching possible base pairing between substrate RNAs and their corresponding 3' truncated tRNA, suggested a unified model for substrate recognition mechanism, in which a four-nucleotide (nt) sequence in the target tRNAs 1 nt upstream of their cleavage site, base pairs with the 5' terminal 4 nt sequence of their corresponding 3' truncated tRNA. This model was supported by experiments with several RNA substrates containing a substituted nucleotide in the target 4 nt sequence, In this model, the tRNA substrates and their corresponding 3' truncated tRNA form a complex resembling a 5' processed tRNA precursor containing a 3' trailer, suggesting that the protein component of RNase 65 is identical to tRNA 3' processing endoribonuclease (3' tRNase), Actually 3' tRNase purified from pig liver cleaved the target RNAs at the expected site only in the presence of their corresponding 3' truncated tRNA, These results show that the 3' tRNase can be converted to 4 nt specific RNA cutters using the 3' truncated tRNAs.