A four-nucleotide translation enhancer in the 3′-terminal consensus sequence of the nonpolyadenylated mRNAs of rotavirus
A four-nucleotide translation enhancer in the 3′-terminal consensus sequence of the nonpolyadenylated mRNAs of rotavirus
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DOI：
10.1017/s1355838200992264
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发表时间：
2000-06-01
期刊：
影响因子：
4.5
通讯作者：
Patton, JT
中科院分区：
文献类型：
--
作者：
Chizhikov, V;Patton, JT
真核 mRNA 的 5' 帽和 Poly(A) 尾协同作用，通过一个需要帽相关真核起始因子 eF-4G 和 Poly(A) 结合蛋白 PABP 相互作用的过程来增强翻译。由于轮状病毒和呼肠孤病毒科其他成员的 mRNA 含有帽子但缺乏聚腺苷酸尾，因此它们的翻译可能通过独特的机制得到增强。为了鉴定病毒 mRNA 中刺激体内翻译的翻译增强元件，制备了嵌合 RNA，其中包含荧光素酶的开放阅读框以及轮状病毒 mRNA 或非病毒 mRNA 的 5' 和 3' 非翻译区 (UTR)。将嵌合RNA转染到轮状病毒感染的细胞中表明，病毒3'UTR含有促进基因表达的翻译增强元件。该元件不会增强未感染细胞中的基因表达，也不会影响 RNA 的稳定性。诱变表明位于轮状病毒 mRNA 3' 端的保守序列 GACC 作为增强元件发挥作用。 3'-GACC 元件独立于 5' UTR 序列刺激蛋白质表达，尽管有效表达需要 RNA 包含帽子。结果表明，轮状病毒感染细胞中病毒蛋白的表达受到病毒 11 个非聚腺苷酸化 mRNA 共有的新型 4-nt 3' 翻译增强子 (TE) 活性的特异性上调。轮状病毒 3' TE 的 4-nt 序列是迄今为止已知的刺激翻译的序列增强子中最短的。
The 5' cap and poly(A) tail of eukaryotic mRNAs work synergistically to enhance translation through a process that requires interaction of the cap-associated eukaryotic initiation factor, elF-4G, and the poly(A)-binding protein, PABP. Because the mRNAs of rotavirus, and other members of the Reoviridae, contain caps but lack poly(A) tails, their translation may be enhanced through a unique mechanism. To identify translation enhancement elements in the viral mRNAs that stimulate translation in vivo, chimeric RNAs were prepared that contained an open reading frame for luciferase and the 5' and 3' untranslated regions (UTRs) of a rotavirus mRNA or of a nonviral mRNA. Transfection of the chimeric RNAs into rotavirus-infected cells showed that the viral 3' UTR contained a translation-enhancement element that promoted gene expression. The element did not enhance gene expression In uninfected cells and did not affect the stability of the RNAs. Mutagenesis showed that the conserved sequence GACC located at the 3' end of rotavirus mRNAs operated as an enhancement element. The 3'-GACC element stimulated protein expression independently of the sequence of the 5' UTR, although efficient expression required the RNA to contain a cap. The results indicate that the expression of viral proteins in rotavirus-infected cells is specifically up-regulated by the activity of a novel 4-nt 3' translation enhancer (TE) common to the 11 nonpolyadenylated mRNAs of the virus. The 4-nt sequence of the rotavirus 3' TE represents by far the shortest of any of the sequence enhancers known to stimulate translation.