MECHANICS OF HANTAVIRAL NUCLEOCAPSID PROTEIN MEDIATED TRANSLATION INITIATION OF

该子项目是利用 由NIH/NCRR资助的中心赠款提供的资源。子项目和 研究者（PI）可能从另一个NIH来源获得主要资金， 因此可以在其他CRISP条目中表示。列出的机构是 中心，不一定是研究者的机构。 真核翻译开始于mRNA帽处的eIF 4F复合物的募集以及mRNA 5'末端处的43 S前起始复合物的接合。几种病毒利用的另一种充分表征的机制包括IRES翻译起始策略，其在mRNA上内部加载核糖体，不依赖于5'帽。汉坦病毒是布尼亚病毒科的成员，是通过不同的新机制启动mRNA翻译的新兴病毒，其使用病毒衣壳蛋白（N）接合mRNA帽处的核糖体，而不依赖于真核IF 4F复合物。我们将进一步表征N介导的翻译起始机制，并说明这种有利于病毒在感染细胞中复制的新策略的可能益处。我们将确定与N相互作用的43 S前起始复合物的组分。N以高亲和力特异性结合病毒mRNA 5' UTR，并在体外参考促进病毒mRNA的翻译。我们将鉴定和表征病毒mRNA 5' UTR上N的结合位点，并确定N是否优先促进宿主细胞中病毒RNA的翻译。N也是解开RNA双链体的RNA分子伴侣。然而，这种RNA伴侣活性不参与N介导的mRNA翻译。在核糖体扫描和AUG密码子鉴定过程中，mRNA 5' UTR中的二级结构被eIF 4A（eIF 4F复合物的组分）去除。由于N在功能上取代了eIF 4F复合物，我们假设N将加载的核糖体从5'帽易位到AUG密码子，避免了5'前导序列的常规扫描。已经设计了多方面的实验方法来验证这一假设。我们将使用多种实验方法来检查N介导的翻译策略是否是针对宿主细胞抗病毒反应的病毒对策。

This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Eukaryotic translation begins with recruitment of eIF4F complex at mRNA cap with the engagement of 43S pre-initiation complex at mRNA 5' terminus. Another well characterized mechanism utilized by several viruses includes IRES translation initiation strategy that internally loads ribosomes on mRNA, independent of 5' cap. Hantaviruses, members of the Bunyaviridae family are emerging viruses that initiate mRNA translation by a different novel mechanism, using viral capsid protein (N) to engage the ribosome at mRNA cap, independent of eukaryotic IF4F complex. We will further characterize N mediated translation initiation mechanism and illustrate possible benefits of this novel strategy that favor virus replication in infected cells. We will identify the components of 43S pre-initiation complex that interact with N. N specifically binds the viral mRNA 5' UTR with high affinity and referentially facilitates the translation of viral mRNAs in vitro. We will identify and characterize the binding site for N on viral mRNA 5' UTR and will determine whether N preferentially facilitates the translation of viral RNAs in host cells. N is also an RNA chaperone that unwinds RNA duplexes. However, this RNA chaperone activity is not involved in N mediated mRNA translation. Secondary structures in mRNA 5' UTR are removed by eIF4A (a component of eIF4F complex) during ribosome scanning and identification of AUG codon. Since N functionally supplants eIF4F complex, we hypothesize that N translocates the loaded ribosomes from 5' cap to the AUG codon, avoiding the regular scanning of 5' leader. Multifaceted experimental approaches have been designed to test this hypothesis. We will use multiple experimental approaches to check whether N mediated translation strategy is a viral counter measure against host cell antiviral response.