A mouse cytoplasmic exoribonuclease (mXRN1p) with preference for G4 tetraplex substrates.
A mouse cytoplasmic exoribonuclease (mXRN1p) with preference for G4 tetraplex substrates.
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DOI：
10.1083/jcb.136.4.761
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发表时间：
1997-02-24
期刊：
影响因子：
--
通讯作者：
Heyer WD
中科院分区：
文献类型：
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作者：
Bashkirov VI;Scherthan H;Solinger JA;Buerstedde JM;Heyer WD
外切核糖核酸酶是细胞RNA种类周转的重要酶。我们从老鼠中分离出了首个被证明编码5′–3′外切核糖核酸酶的哺乳动物cDNA。预测蛋白质的结构保守性以及在酿酒酵母中的互补数据表明，它在细胞质mRNA周转和前rRNA加工中的作用类似于酵母中主要的细胞质外切核糖核酸酶Xrn1p。因此，酿酒酵母中mRNA降解系统的一个关键成分在从酵母到哺乳动物的进化过程中是保守的。纯化的小鼠蛋白质（mXRN1p）在结合和水解实验中显示出对含G4 RNA四链体底物的新型底物偏好。mXRN1p是第一个定位在哺乳动物细胞细胞质中的RNA周转功能蛋白。mXRN1p分布在小颗粒中，并在离散的、显著的焦点处高度富集。mXRN1p的特异性表明，含有G4四链体结构的RNAs可能在体内存在，并可能在RNA周转中起作用。
Exoribonucleases are important enzymes for the turnover of cellular RNA species. We have isolated the first mammalian cDNA from mouse demonstrated to encode a 5′–3′ exoribonuclease. The structural conservation of the predicted protein and complementation data in Saccharomyces cerevisiae suggest a role in cytoplasmic mRNA turnover and pre-rRNA processing similar to that of the major cytoplasmic exoribonuclease Xrn1p in yeast. Therefore, a key component of the mRNA decay system in S. cerevisiae has been conserved in evolution from yeasts to mammals. The purified mouse protein (mXRN1p) exhibited a novel substrate preference for G4 RNA tetraplex–containing substrates demonstrated in binding and hydrolysis experiments. mXRN1p is the first RNA turnover function that has been localized in the cytoplasm of mammalian cells. mXRN1p was distributed in small granules and was highly enriched in discrete, prominent foci. The specificity of mXRN1p suggests that RNAs containing G4 tetraplex structures may occur in vivo and may have a role in RNA turnover.