Demonstrating the mechanism of Nairovirus translation strategy

摘要：克里米亚刚果出血热是一种扁虱传播、高传染性、高死亡率的病毒性疾病。 在人类中的比率。目前还没有针对这种病毒性疾病的治疗方法。我们最近报道，克里米亚刚果 出血热病毒核衣壳蛋白(CCHFV N蛋白)具有两个不同的RNA结合部位。 茎域和头域。位于头部结构域中的RNA结合位点非特异性地与单个 病毒或非病毒来源的链RNA。然而，位于茎结构域中的RNA结合位点具体 结合到由高度保守的和 病毒基因组5‘和3’末端的互补核苷酸。有趣的是病毒mRNA5‘端非编码区 也折叠成狭长柄状的二级结构，这也是由 N蛋白。N蛋白与病毒mRNA5‘端非编码区相互作用促进下游翻译 开放阅读框架(ORF)。大多数真核细胞的mrna翻译是依赖m7G帽的，并且是启动的 通过组装eIF4F帽结合复合体，由eIF4E、eIF4A和eIF4G三个启动因子组成。 我们的初步数据表明，N蛋白介导的翻译策略不需要组装eIF4F 复杂，但这个复合体的各个组件的结构完整性是这种病毒所必需的 翻译机制。这一公布的数据表明，CHFV N蛋白很可能诱使宿主翻译 在感染过程中优先翻译病毒mRNA的装置，以促进 病毒在感染细胞中的mRNA。我们将使用多方面的实验方法来检验这一假设 CCHFV N蛋白与eIF4F复合体成分相互作用选择性结合40S核糖体 病毒mRNA5‘端非编码区的亚基。由于核糖体负载在mRNA上是一个关键的速率限制步骤 真核翻译，CCHFV N蛋白可能通过选择性地在这一关键步骤帮助病毒转录本 将宿主细胞核糖体连接到病毒mRNA5‘端非编码区。这种选择性的核糖体装载可能有助于病毒 通过避免来自宿主细胞转录的竞争，相同的宿主翻译机制。我们 将确定CCHFV N蛋白介导的翻译策略是否选择性地促进了 病毒在感染过程中的mRNA。

Abstract: Crimean Congo hemorrhagic fever is a tick born, highly contagious, viral illness with high mortality rates in humans. There is no treatment for this viral disease at present. We recently reported that Crimean Congo hemorrhagic fever virus nucleocapsid protein (CCHFV N protein) has two distinct RNA binding sites in the stalk and head domains. The RNA binding site located in the head domain non-specifically binds to the single strand RNA of viral or nonviral origin. However, the RNA binding site located in the stalk domain specifically binds to the double strand panhandle structure formed by the base pairing of highly conserved and complementary nucleotides at the 5’ and 3’ termini of the viral genome. Interestingly the viral mRNA 5’ UTR also folds into a panhandle-like secondary structure, which is also specifically recognized by the stalk domain of N protein. The interaction between N protein and viral mRNA 5’ UTR facilitates the translation of downstream open reading frame (ORF). The majority of eukaryotic mRNA translation is m7G cap dependent and is initiated by the assembly of eIF4F cap binding complex, composed of three initiation factors eIF4E, eIF4A and eIF4G. Our preliminary data shows that N protein mediated translation strategy does not require the assembly of eIF4F complex but the structural integrity of individual components of this complex is required for this viral translation mechanism. This published data suggests that CHFV N protein highly likely lures the host translation apparatus for the preferential translation of viral mRNA during the course of infection, to boost the translation of viral mRNA in the infected cell. We will use multifaceted experimental avenues to test the hypothesis that CCHFV N protein interacts with the components of eIF4F complex to selectively engage the 40S ribosomal subunits on the viral mRNA 5’ UTR. Since ribosome loading on mRNA is a critical rate limiting step in eukaryotic translation, CCHFV N protein likely helps the viral transcripts at this critical step by selectively engaging the host cell ribosomes on viral mRNA 5’ UTR. This selective ribosome loading likely helps viral transcripts by avoiding the competition from host cell transcripts for the same host translation machinery. We will determine whether CCHFV N protein mediated translation strategy selectively facilitates the translation of viral mRNA during the course of infection.