Marburg and Ebola Virus mRNA 3' Untranslated Regions Contain Negative Regulators of Translation That Are Modulated by ADAR1 Editing.
Marburg and Ebola Virus mRNA 3' Untranslated Regions Contain Negative Regulators of Translation That Are Modulated by ADAR1 Editing.
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DOI：
10.1128/jvi.00652-21
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发表时间：
2021-09-09
影响因子：
5.4
通讯作者：
Basler CF
中科院分区：
文献类型：
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作者：
Khadka S;Williams CG;Sweeney-Gibbons J;Basler CF
丝状病毒家族包括致命的病原体，例如埃博拉病毒（EBOV）和马尔堡病毒（MARV）。丝状病毒基因组的很大一部分编码病毒mRNA的5 ′和3 ′非翻译区（UTR）。选择对应于3 ′ UTR的病毒基因组RNA序列易于被作用于RNA 1的腺苷脱氨酶（ADAR 1）编辑。一种报告基因mRNA方法，将不同的5 ′或3 ′ UTR插入到编码内切酶的mRNA中，证明MARV 3 ′ UTR产生不同水平的报告基因表达，表明翻译的调节。这种调节发生在不能产生微小RNA（miRNA）的细胞中，并且可以在MARV微型基因组测定中重现。缺失突变体在MARV核蛋白（NP）和大蛋白（L）3 ′ UTR末端鉴定出负调控区。先前在MARV NP 3 ′ UTR内鉴定了明显的ADAR 1编辑突变体。如报告基因分析和多核糖体分析所示，将这些变化引入MARV核蛋白（NP）3 ′ UTR或缺失靶向编辑区域可增强翻译。此外，亲本NP 3 ′ UTR，而不是编辑的或缺失的突变体NP 3 ′ UTR，在转染到细胞中后诱导I型干扰素（IFN）应答。由于来自西非爆发的一些EBOV分离株显示40 kDa（VP40）3 ′ UTR的病毒蛋白的ADAR 1编辑，因此对具有亲本和编辑序列的VP40 3 ′ UTR进行了类似的测定。EBOV VP40 3 ′ UTR编辑也增强了翻译，但野生型和编辑的3 ′ UTR都不诱导IFN。这些发现暗示丝状病毒mRNA 3 ′ UTR是翻译的负调节因子，可以通过诱导ADAR 1的先天免疫反应失活。UTR在丝状病毒基因组中占很大比例，是ADAR 1编辑的明显靶标，ADAR 1是一种具有促病毒和抗病毒活性的酶。然而，UTR和ADAR 1编辑的功能意义尚不确定。这项研究表明，MARV和EBOV 3 ′ UTR可以调节翻译，在某些情况下是负面的。编辑或删除翻译抑制3 ′ UTR内的选定区域可减轻UTR的负面影响。这些数据表明，丝状病毒3 ′ UTR含有由ADAR 1激活调节的翻译调控元件，表明丝状病毒基因表达和先天免疫之间存在复杂的相互作用。
The filovirus family includes deadly pathogens such as Ebola virus (EBOV) and Marburg virus (MARV). A substantial portion of filovirus genomes encode 5′ and 3′ untranslated regions (UTRs) of viral mRNAs. Select viral genomic RNA sequences corresponding to 3′ UTRs are prone to editing by adenosine deaminase acting on RNA 1 (ADAR1). A reporter mRNA approach, in which different 5′ or 3′ UTRs were inserted into luciferase-encoding mRNAs, demonstrates that MARV 3′ UTRs yield different levels of reporter gene expression, suggesting modulation of translation. The modulation occurs in cells unable to produce microRNAs (miRNAs) and can be recapitulated in a MARV minigenome assay. Deletion mutants identified negative regulatory regions at the ends of the MARV nucleoprotein (NP) and large protein (L) 3′ UTRs. Apparent ADAR1 editing mutants were previously identified within the MARV NP 3′ UTR. Introduction of these changes into the MARV nucleoprotein (NP) 3′ UTR or deletion of the region targeted for editing enhances translation, as indicated by reporter assays and polysome analysis. In addition, the parental NP 3′ UTR, but not the edited or deletion mutant NP 3′ UTRs, induces a type I interferon (IFN) response upon transfection into cells. Because some EBOV isolates from the West Africa outbreak exhibited ADAR1 editing of the viral protein of 40 kDa (VP40) 3′ UTR, VP40 3′ UTRs with parental and edited sequences were similarly assayed. The EBOV VP40 3′ UTR edits also enhanced translation, but neither the wild-type nor the edited 3′ UTRs induced IFN. These findings implicate filoviral mRNA 3′ UTRs as negative regulators of translation that can be inactivated by innate immune responses that induce ADAR1. IMPORTANCE UTRs comprise a large percentage of filovirus genomes and are apparent targets of editing by ADAR1, an enzyme with pro- and antiviral activities. However, the functional significance of the UTRs and ADAR1 editing has been uncertain. This study demonstrates that MARV and EBOV 3′ UTRs can modulate translation, in some cases negatively. ADAR1 editing or deletion of select regions within the translation suppressing 3′ UTRs relieves the negative effects of the UTRs. These data indicate that filovirus 3′ UTRs contain translation regulatory elements that are modulated by activation of ADAR1, suggesting a complex interplay between filovirus gene expression and innate immunity.