Recruitment of host noncoding RNAs by XMRV

描述（由申请方提供）：两种人类逆转录病毒，即人类免疫缺陷病毒1型（HIV-1）（导致获得性免疫缺陷综合征）和人类T细胞白血病病毒1型（HTLV-1）（导致成人T细胞白血病和淋巴瘤），在全球范围内造成显著的死亡率和发病率。这个探索性项目的目的是确定是否逆转录病毒的一个相对未研究的方面，它们倾向于非随机地将宿主非编码RNA招募到病毒体中，可以被利用来深入了解逆转录病毒生物学，识别抗病毒药物的潜在新靶点，并设计“特洛伊RNA”变体，在包装时干扰基本过程。特别关注的是一种新的人类逆转录病毒，称为异嗜性小鼠白血病病毒相关病毒（XMRV），最近在一些前列腺肿瘤和一些慢性疲劳综合征患者中发现。虽然目前还没有确定XMRV是否有助于这两种疾病的发病机制，但人类携带一种新型传染性逆转录病毒的发现仍然是一个值得关注的重要原因。尽管非编码RNA被逆转录病毒包装已经有40年的历史，但被包装的RNA的谱是未知的，它们在逆转录病毒生物学中的作用知之甚少，它们作为抗病毒靶点的潜力也没有被探索。我们选择XMRV进行这些实验是因为它与两种疾病的潜在联系以及它与MoMuLV的密切同源性，MoMuLV是宿主RNA降解研究最好的逆转录病毒。第一个目标是使用深度测序技术来阐明XMRV包装的宿主RNA的完整集合。第二个目的是确定通过XMRV包装宿主RNA的分子基础和功能相关性。对于那些我们发现是病毒粒子的化学计量组分的RNA，我们将确定病毒和RNA中赋予包装的决定因素。我们还将测试阻止这些宿主RNA的包装是否会影响病毒的组装或功能。根据特定的RNA，这将涉及直接用siRNA耗尽RNA或耗尽稳定RNA的蛋白质伴侣。对于那些被包装为新合成的转录物的宿主RNA，我们也将尝试通过过表达伴侣蛋白来减少包装，以驱动更多的RNA进入成熟的RNP。第三个目标是开发高度包装的宿主RNA的病毒毒性衍生物。对于每种潜在的病毒毒性衍生物，我们将评估其在宿主细胞中的表达，其通过XMRV的包装，以及RNA的存在是否影响病毒产量或感染性。总之，这些实验应该使我们能够阐明一套主机非编码RNA，有助于XMRV的生命周期，并可能提供设计新类别的抗病毒药，目标XMRV和已知的致病性逆转录病毒，如HIV-1和HTLV-1的范例。 公共卫生相关性：逆转录病毒如HIV-1会导致严重的疾病，如艾滋病，影响全世界数百万人。在一些前列腺肿瘤和一些慢性疲劳综合征患者中发现了一种新的逆转录病毒，称为XMRV。这项提案测试了XMRV和其他逆转录病毒从感染细胞中捕获RNA分子的趋势是否可以用来识别设计抗病毒药物的新靶点。

DESCRIPTION (provided by applicant): Two human retroviruses, human immunodeficiency virus type 1 (HIV-1), the cause of acquired immune deficiency syndrome, and human T-cell leukemia virus type 1 (HTLV-1), which causes adult T-cell leukemias and lymphomas, are responsible for significant mortality and morbidity worldwide. The objective of this exploratory project is to determine whether a relatively unstudied aspect of retroviruses, their propensity to non-randomly recruit host noncoding RNAs into virions, can be exploited to gain insights into retroviral biology, to identify potential new targets for antivirals, and to engineer "Trojan RNA" variants that, upon packaging, interfere with essential processes. The specific focus is on a new human retrovirus, called Xenotropic murine leukemia virus-related virus (XMRV), which was recently identified in some prostate tumors and in some patients with chronic fatigue syndrome. Although it is not yet established whether XMRV contributes to the pathogenesis of either disease, the finding that humans harbor a novel infectious retrovirus is nonetheless a significant cause for concern. Although noncoding RNAs have been known to undergo packaging by retroviruses for forty years, the spectrum of RNAs encapsidated is unknown, their roles in retrovirus biology are poorly understood, and their potential as antiviral targets has not been explored. We chose XMRV for these experiments because of its potential link to two diseases and for its close homology to MoMuLV, the retrovirus in which host RNA encapsidation has been best studied. The first aim is to use deep sequencing technology to elucidate the complete set of host RNAs packaged by XMRV. The second aim is to determine the molecular basis and functional relevance of host RNA packaging by XMRV. For those RNAs that we find to be stoichiometric components of virions, we will identify the determinants within both the virus and the RNA that confer packaging. We will also test if preventing packaging of these host RNAs affects virus assembly or function. Depending on the particular RNA, this will involve either depleting the RNA directly with siRNAs or depleting protein partners that stabilize the RNA. For those host RNAs that are packaged as newly synthesized transcripts, we will also try to decrease packaging by overexpressing partner proteins to drive more of the RNAs into the mature RNPs. The third aim is to develop virotoxic derivatives of highly packaged host RNAs. For each potential virotoxic derivative, we will assess its expression in host cells, its packaging by XMRV, and whether the presence of the RNA affects virus yield or infectivity. Together, these experiments should allow us to elucidate the set of host noncoding RNAs that contribute to the XMRV lifecycle and may provide paradigms for designing new classes of antiviral agents that target both XMRV and known pathogenic retroviruses such as HIV-1 and HTLV-1. PUBLIC HEALTH RELEVANCE: Retroviruses such as HIV-1 cause serious illnesses, such as AIDS, that affect millions of people worldwide. A new retrovirus, called XMRV, was identified in some prostate tumors and in some people with chronic fatigue syndrome. This proposal tests whether the tendency of XMRV and other retroviruses to capture RNA molecules from infected cells can be used to identify new targets for designing antiviral drugs.