Virus-host interactions in frog virus 3 infected cells

这项提案中概述的研究旨在利用一种科学上尚未开发但具有重要经济意义的病毒家族-虹彩病毒科-来识别新型病毒-宿主相互作用基因，这些基因将有助于识别以前未识别的细胞抗病毒途径。我们之所以选择观察虹彩病毒科中病毒与宿主的相互作用，原因有很多。首先，与疱疹病毒科和痘病毒科不同，对虹彩病毒科的生物学缺乏重要的基础研究。其次，通过研究新的病毒家族，可以识别针对未鉴定的宿主抗病毒策略的新基因。最后，许多虹彩病毒科已被证实是鱼类和野生动物严重疾病的病原体，影响水产养殖和野生动物保护。为了了解虹彩病毒科是如何绕过宿主防御的，我们选择了虹彩病毒科中研究最多的成员青蛙病毒3(FV3)作为我们的模型系统。FV3的基因组序列显示了一个与LITAF有显著同源性的基因75L。75L是一种由84个氨基酸组成的蛋白质，与细胞LITAF的C端序列相同，但缺少LITAF的N端。由于75L与LITAF的相似性，我们推测75L干扰了LITAF的功能。具体地说，我们认为75L以一种显性的负向方式发挥作用，通过介导LITAF的C-末端一半的相互作用来拮抗细胞的LITAF功能，但缺乏LITAF的N-末端结合位点。由于LITAF的作用尚不清楚，我们对这一独特细胞基因功能的研究将有助于解释与LITAF突变相关的神经退行性疾病，以及推进病毒的致病机制。最后，这里的研究将有助于理解FV3是如何导致疾病的，并可能有助于管理自然人群中的病毒爆发。

The research outlined in this proposal is aimed at using a scientifically unexploited but economically important virus family, the Iridoviridae, to identify novel classes of virus-host interacting genes that will help identify previously unidentified cellular anti-viral pathways. We have chosen to look at virus-host interactions in the Iridoviridae for a number of reasons. First, unlike the Herpesviridae and Poxviridae families, there is a lack of significant basic research into the biology of the Iridoviridae. Secondly, by examining new viral families, novel genes that target uncharacterized host anti-viral strategies can be identified. Finally, many Iridoviridae have been confirmed as the causative agent of severe diseases in fish and wildlife, affecting aquaculture and wildlife conservation. To understand how the Iridoviridae family circumvents host defenses, we chose frog virus 3 (FV3), the best-studied member of the Iridoviridae family, as our model system. The genomic sequence of FV3 revealed a gene, 75L that has striking homology to LITAF. 75L is an 84 amino acid protein that has sequence identity with the C-terminus of cellular LITAF, but lacks the N-terminus of LITAF. Because of the similarities between 75L and LITAF, we hypothesize that 75L interferes with LITAF's function. Specifically, we propose that 75L functions in a dominant negative fashion, antagonizing cellular LITAF function by mediating interactions through the C-terminal half of LITAF but lacking the N-terminal binding sites of LITAF. Since the role of LITAF is unknown, our research into the function of this unique cellular gene will help explain the neurodegenerative disease that is associated with mutations in LITAF, as well as advancing viral pathogenesis. Finally, the studies here will help understand how FV3 causes disease and may help management of viral outbreaks in natural populations.