HIV and ADAR Editing

描述（由申请人提供）：ADAR（腺苷脱氨酶作用于RNA）家族的蛋白质催化人类细胞中mRNA中最常见的RNA编辑事件，A到I脱氨。ADAR特异性地编辑双链RNA区域的残基。ADAR活性导致在较短、不完整的茎中选择性编辑，而较长的完全双链区域通常被更广泛地编辑。ADAR活性起着重要的生理作用，与癌症、发育和RNAi有关。ADAR蛋白也被证明是许多病毒复制的重要因素。然而，迄今为止只有少数研究涉及到ADAR基因对HIV复制的影响。ADAR1对hiv的作用仍然存在争议，有正面和负面作用的报道，而只有一项关于ADAR2作用的已发表研究。ADAR作用的分子机制仍有待阐明。ADAR基因可能是由一个共同的祖先产生的，这个祖先也产生了另一个编辑酶家族——载脂蛋白激酶蛋白。这些蛋白最近被提出在HIV进化和免疫逃避中发挥潜在的作用，除了它们在HIV限制中的作用。我们的假设是，ADAR蛋白也被HIV利用，不仅用于调控，还用于进化和免疫逃避。因此，我们建议开展研究，系统地、广泛地分析ADAR对HIV的作用。首先，我们将确定ADAR如何编辑HIV mrna中的干区，以及这与RNA运输途径的关系。其次，我们将以治疗性HIV反义RNA为模型，分析HIV正义/反义RNA杂交体的ADAR编辑。具体目标1：分析ADAR1和ADAR2如何在HIV mRNA中编辑茎环区域，以及是否根据mRNA输出途径发生差异编辑。特异性目的2：分析ADAR如何影响HIV反义靶区反义RNA介导的抑制和RNA编辑。

DESCRIPTION (provided by applicant): Proteins of the ADAR (adenosine deaminases acting on RNA) family catalyze the most common RNA editing event in mRNA in human cells, A to I deamination. ADAR specifically edits residues in regions of double stranded RNA. ADAR activity results in selective editing in shorter, imperfect stems, whereas long perfectly double stranded regions are usually more extensively edited. ADAR activity plays an important physiological role and has been implicated in cancer, development and RNAi. ADAR proteins have also been shown to be important factors in the replication of many viruses. However, only a few studies to date have dealt with the effects of ADAR genes on HIV replication. The effects of ADAR1 on HIV1 remain controversial, with reports of both positive and negative effects, whereas there is only one published study of the effects of ADAR2. The molecular mechanism underlying ADAR effects remain to be elucidated. The ADAR genes were likely generated from a common ancestor that also gave rise to another family of editing enzymes, the ApoBec proteins. These proteins have recently been proposed to potentially play a role in HIV evolution and immune evasion, in addition to their roles in HIV restriction. Our hypothesis is that ADAR proteins are also used by HIV, not only for regulation, but also for evolution and immune evasion. We thus propose to initiate studies to systematically and extensively analyze the effects of ADAR on HIV. First we will determine how ADAR edits stem regions in the HIV mRNAs and how this relates to RNA trafficking pathways. Secondly, we will analyze ADAR editing of HIV sense/antisense RNA hybrids, using a therapeutic HIV antisense RNA as a model. Specific Aim 1: To analyze how ADAR1 and ADAR2 function to edit stem-loop regions in HIV mRNAs and if differential editing occurs depending on the mRNA export pathway. Specific Aim 2: To analyze how ADAR affects antisense RNA mediated inhibition and RNA editing in HIV antisense target regions.