Virus-host interactions in frog virus 3 infected cells

背景：本提案的目的是了解一个相对未被研究过的大型DNA病毒群——虹膜病毒科——所采用的病毒与宿主的相互作用。了解病毒-宿主相互作用基因将使我们能够探索新的抗病毒策略，为免疫系统的功能提供新的见解，并了解病毒感染如何导致病毒发病。尽管基于与其他病毒或细胞基因的序列相似性已经确定了许多潜在的鸢尾病毒科宿主抗病毒机制调节剂，但这些基因中很少有被表征。因此，我们将利用鸢尾病毒科中研究最多的成员青蛙病毒3 （FV3）来研究宿主防御机制的病毒调节剂。本提案将描述FV3基因75L。先前，我们的实验室发现75L与LITAF结合，并且FV3感染的存在诱导LITAF的表达。假设：我们假设LITAF是保守的细胞防御通路的一部分，因为它的表达在FV3感染后被打开。我们进一步假设75L可能拮抗LITAF的功能，因为我们已经证明75L与LITAF结合。在本提案中，我们将探讨FV3-75L是否可以抑制LITAF功能。我们还将确定LITAF是否代表了一种未表征的细胞宿主防御机制。为了实现这些目标，我们建议：***1)确定75L是否抑制LITAF功能。LITAF已被证明在多种细胞表面受体的降解和诱导TNF-a表达中起作用。我们将确定75L是否可以抑制这些功能。***2)确定LITAF是否影响FV3复制。使用各种检测方法监测病毒复制周期的不同阶段，我们将确定当75L蛋白减少或缺失时病毒复制是否受损。***3)确定病毒感染后LITAF是如何诱导的。由于LITAF是在FV3感染时表达的，我们想确定FV3感染是如何诱导LITAF的。为了验证这一点，我们将确定FV3是否通过刺激LITAF表达的已知途径诱导LITAF。***意义：本文研究的目的是表征虹膜病毒科病毒-宿主相互作用基因。本提案侧重于FV3及其与LITAF的交互。由于LITAF在病毒感染中的功能尚不清楚，我们的研究不仅将阐明LITAF的生物学功能，还将阐明75L如何介导LITAF的抑制。此外，由于LITAF突变可导致人类神经退行性疾病Charcot-Marie Tooth disease (CMT)，我们对LITAF的持续表征将有助于理解LITAF突变如何导致CMT，并为该疾病的潜在治疗提供见解。**

Background: The goal of this proposal is to understand virus-host interactions employed by a relatively unstudied group of large DNA viruses - the Iridoviridae family. Understanding virus-host interacting genes will allow us to explore novel anti-viral strategies, provide new insight into the function of the immune system, and understand how virus infections lead to viral pathogenesis. Although a number of potential Iridoviridae modulators of host anti-viral mechanisms have been identified based on sequence similarity to other viral or cellular genes, few of these genes have been characterized. Therefore, we will use frog virus 3 (FV3), the best-studied member of the Iridoviridae family, to investigate viral modulators of host defense mechanisms. This proposal will characterize the FV3 gene 75L. Previously, our lab showed that 75L binds to LITAF and that the presence of an FV3 infection induces the expression of LITAF.***Hypothesis: We hypothesize that LITAF is part of a conserved cellular defense pathway as its expression is turned on after FV3 infection. We further hypothesize that 75L may antagonize LITAF's function since we have shown that 75L binds to LITAF. In this proposal we will explore whether FV3-75L can inhibit LITAF function. We will also determine whether LITAF represents an uncharacterized cellular host defense mechanism. To achieve these goals, we propose to:***1) Determine if 75L inhibits LITAF function. LITAF has been shown to function in the degradation of a variety of cell surface receptors and induce TNF-a expression. We will determine whether 75L can inhibit these functions.***2) Determine if LITAF affects FV3 replication. Using a variety of assays that monitor different stages of the viral replication cycle, we will determine if viral replication is impaired when 75L protein is reduced or absent.***3) Determine how LITAF is induced upon viral infection. Since LITAF is expressed in response to an FV3 infection, we wanted to determine how an FV3 infection induces LITAF. To test this, we will determine if FV3 induces LITAF through the known pathways that stimulate LITAF expression. ***Significance: The research outlined in this proposal is aimed at characterizing virus-host interacting genes in the Iridoviridae. This proposal focuses on FV3 and its interactions with LITAF. Since the function of LITAF during a viral infection is unknown, our research will not only elucidate the biological function of LITAF, but will also clarify how 75L mediates the inhibition of LITAF. In addition, since mutations in LITAF can cause the human neurodegenerative disease Charcot-Marie Tooth disease (CMT), our continued characterization of LITAF will help in understanding how mutations in LITAF cause CMT and provide insight into potential therapies for this disease.**