A mutated human homologue to yeast Upf1 protein has a dominant-negative effect on the decay of nonsense-containing mRNAs in mammalian cells
A mutated human homologue to yeast Upf1 protein has a dominant-negative effect on the decay of nonsense-containing mRNAs in mammalian cells
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DOI：
10.1073/pnas.95.17.10009
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发表时间：
1998-08-18
影响因子：
11.1
通讯作者：
Maquat, LE
中科院分区：
文献类型：
--
作者：
Sun, XL;Perlick, HA;Maquat, LE
所有被分析的真核细胞都已经开发出机制来消除过早终止翻译的mRNAs的产生。这些机制被认为是为了保护细胞免受框架内无意义密码子的有害影响，这些框架内无意义密码子是由RNA新陈代谢中的常规低效和不准确产生的，例如前mRNA剪接。根据特定的信使核糖核酸及其产生方式，无义密码子可以在以下两种情况下调节信使核糖核酸丰度的降低：(I)在与细胞核结合释放到细胞质之前，推测但不一定是当信使核糖体输出到细胞质并被胞浆核糖体翻译时，或者(Ii)在细胞质中，我们为在哺乳动物细胞中消除含有无义密码子的RNA的产生提供了证据。该因子被不同地称为Rent1(无义转录调节因子)或HUPF1(人UPF1蛋白)，通过分离酿酒酵母Upf1p的人同源物的cDNA来鉴定，酿酒酵母Upf1p是一种I族RNA解旋酶，在酵母中无义介导的mRNA的衰退中发挥作用。利用猴COS细胞和人HeLa细胞，我们证明了在RNA解旋酶结构域中含有844位精氨酸到半胱氨酸突变的人UPF1蛋白的表达以显性-负向的方式作用，以消除(I)与细胞核或(Ii)在细胞质中发生的含有无义的mRNA的衰退。这些发现提供了证据，证明在酵母和哺乳动物细胞中，无义介导的mRNA衰退是机械相关的，与衰退的细胞位置无关。
All eukaryotic cells analyzed have developed mechanisms to eliminate the production of mRNAs that prematurely terminate translation. The mechanisms are thought to exist to protect cells from the deleterious effects of in-frame nonsense codons that are generated by routine inefficiencies and inaccuracies in RNA metabolism such as pre-mRNA splicing. Depending on the particular mRNA and how it is produced, nonsense codons can mediate a reduction in mRNA abundance either (i) before its release from an association with nuclei into the cytoplasm, presumably but not certainly while the mRNA is being exported to the cytoplasm and translated by cytoplasmic ribosomes, or (ii) in the cytoplasm, Here, we provide evidence for a factor that functions to eliminate the production of nonsense-containing RNAs in mammalian cells. The factor, variously referred to as Rent1 (regulator of nonsense transcripts) or HUPF1 (human Upf1 protein), was identified by isolating cDNA for a human homologue to Saccharomyces cerevisiae Upf1p, which is a group I RNA helicase that functions in the nonsense-mediated decay of mRNA in yeast. Using monkey COS cells and human HeLa cells, we demonstrate that expression of human Upf1 protein harboring an arginine-to-cysteine mutation at residue 844 within the RNA helicase domain acts in a dominant-negative fashion to abrogate the decay of nonsense-containing mRNA that takes place (i) in association with nuclei or (ii) in the cytoplasm. These findings provide evidence that nonsense-mediated mRNA decay is related mechanistically in yeast and in mammalian cells, regardless of the cellular site of decay.