Recruitment of host noncoding RNAs by XMRV

描述（由申请人提供）：两种人类逆转录病毒，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，在世界范围内造成严重的死亡率和发病率。这个探索性项目的目的是确定逆转录病毒的一个相对未被研究的方面，即它们非随机招募宿主非编码RNA进入病毒粒子的倾向，是否可以被利用来深入了解逆转录病毒生物学，确定抗病毒药物的潜在新靶点，并设计“特洛伊RNA”变体，这些变体在包装时干扰基本过程。具体的重点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了这种病毒。尽管目前尚不清楚XMRV是否与这两种疾病的发病机制有关，但人类携带一种新型传染性逆转录病毒的发现仍然值得关注。尽管人们已经知道非编码rna被逆转录病毒包装了40年，但被封装的rna的光谱是未知的，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尚未被探索。我们之所以选择XMRV进行这些实验，是因为它与两种疾病有潜在的联系，而且它与MoMuLV有密切的同源性，MoMuLV是一种逆转录病毒，在这种逆转录病毒中，宿主RNA的封装被研究得最好。第一个目的是利用深度测序技术来阐明XMRV包装的全套宿主rna。第二个目的是确定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成分的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，这将涉及用sirna直接消耗RNA或消耗稳定RNA的蛋白质伙伴。对于那些被包装为新合成转录物的宿主rna，我们也将尝试通过过度表达伴侣蛋白来减少包装，以驱动更多的rna进入成熟的RNPs。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，XMRV的包装，以及RNA的存在是否影响病毒产量或传染性。总之，这些实验将使我们能够阐明一组与XMRV生命周期有关的宿主非编码rna，并可能为设计针对XMRV和已知致病性逆转录病毒（如HIV-1和HTLV-1）的新型抗病毒药物提供范例。

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.