Regulation of mRNA export during gammaherpesvirus infection

项目总结 卡波西肉瘤相关疱疹病毒(KSHV)或人类疱疹病毒-8(HHV-8)，属于 是人类疱疹病毒的亚家族，是几种人类恶性肿瘤的致病因子。 感染人类免疫缺陷病毒-1(HIV-1)或艾滋病患者。而KSHV疾病的发病率 自采用高效抗逆转录病毒疗法(HARRT)以来显著下降，卡波西肉瘤 (KS)仍然是全世界艾滋病毒和艾滋病患者的主要癌症类型。KSHV主要是 在流行地区通过唾液传播，并经常导致口腔中KS的发展 爱滋病患者。 与所有病毒一样，KSHV操纵宿主基因表达的能力对其生存至关重要。最近我们 发现了一种由KSHV编码的新的转录后机制来实现这一点。KSHV开放阅读 框架10(ORF10)抑制细胞mRNAs的核输出，而不影响自身的转录本。此出口 ORF10的抑制功能需要与RNA输出因子RAE1相互作用。此外，我们还展示了 ORF10的出口抑制对于mRNAs的子集是选择性的，并且 靶基因使转录产物对ORF10介导的出口抑制具有敏感性。一种密切相关的ORF10 啮齿动物病毒，小鼠伽马疱疹病毒68(MHV-68)，也与RAE1相互作用，并负责抑制 MHV-68感染过程中mRNA的核输出。蛋白质相互作用的守恒性和蛋白质功能 不仅强调了在伽马疱疹病毒感染期间规范RNA输出的重要性，而且还 主张将MHV-68作为研究ORF10的体内模型。在这个提案中，我们将阐明分子 ORF10介导的选择性RNA输出抑制机制。这一结果可能会揭示一种新的细胞 对信使核糖核酸输出的调控。此外，我们还将确定ORF10 mRNA输出的功能意义 在伽马疱疹病毒感染过程中的抑制。我们将利用KSHV和MHV-68 ORF10突变体来鉴定 ORF10-在感染背景下宿主基因表达的特异性变化。最后，我们将定义体内的 ORF10在小鼠感染MHV-68ORF10突变株中的作用 这些实验将增加我们对伽马疱疹病毒如何劫持细胞信使核糖核酸输出的理解 促进自身复制的途径。此外，这项研究可能会揭示KSHV的关键细胞功能 并为KSHV相关疾病的新治疗策略提供见解。

PROJECT SUMMARY Kaposi sarcoma-associated herpesvirus (KSHV) or human herpesvirus-8 (HHV-8), belongs to the gamma subfamily of human herpesviruses and is responsible for several human malignancies developed in individuals infected with human immunodeficiency virus-1 (HIV-1) or AIDS patients. While the incidence of KSHV diseases has significantly declined since the introduction of highly active antiretroviral therapy (HARRT), Kaposi Sarcoma (KS) remains to be the major type of cancer worldwide in people living with HIV and AIDS. KSHV is primarily transmitted through saliva in endemic regions and frequently results in the development of KS in the oral cavity of AIDS patients. Like all viruses, the ability of KSHV to manipulate host gene expression is vital for its survival. Recently we discovered a novel post-transcriptional mechanism encoded by KSHV to accomplish this. KSHV open reading frame 10 (ORF10) inhibits nuclear export of cellular mRNAs without affecting its own transcripts. This export inhibitory function of ORF10 requires the interaction with an RNA export factor, Rae1. Furthermore, we showed that export inhibition of ORF10 is selective for a subset of mRNAs, and that the 3' untranslated regions of the targeted genes confer transcript sensitivity to ORF10-mediated export inhibition. ORF10 of a closely related rodent virus, murine gammaherpesvirus 68 (MHV-68), also interacts with Rae1 and is responsible for inhibiting nuclear export of mRNA during MHV-68 infection. The conservation of protein interaction and protein function not only underscores the importance of regulating RNA export during gammaherpesvirus infection, but also argues for MHV-68 as an in vivo model to study ORF10. In this proposal, we will elucidate the molecular mechanisms of ORF10-mediated selective RNA export inhibition. The result may reveal a novel cellular regulation of mRNA export. Furthermore, we will determine the functional significance of ORF10 mRNA export inhibition during gammaherpesvirus infection. We will employ the KSHV and MHV-68 ORF10 mutants to identify ORF10-specific changes on host gene expression in the context of infection. Finally, we will define the in vivo role of ORF10 with mouse infection of the MHV-68 ORF10 mutant. These experiments will increase our understanding of how gammaherpesviruses hijack cellular mRNA export pathway to facilitate their own replication. Moreover, the study may uncover cellular functions critical for KSHV replication and provide insights into new therapeutic strategies for KSHV-associated diseases.