HIV and ADAR Editing

描述(申请人提供)：ADAR(作用于RNA的腺苷脱氨酶)家族的蛋白质催化人类细胞中最常见的RNA编辑事件，A到I脱氨作用。ADAR专门编辑双链RNA区域的残基。ADAR活性导致选择性编辑较短、不完美的茎，而长的完全双链区域通常编辑得更广泛。ADAR活性在肿瘤的发生、发展和RNAi中起着重要的生理作用。ADAR蛋白也被证明是许多病毒复制的重要因素。然而，到目前为止，只有少数研究涉及ADAR基因对艾滋病毒复制的影响。ADAR1对HIV1的影响仍然存在争议，有正面和负面的报道，而关于ADAR2的影响只有一项已发表的研究。ADAR效应的分子机制尚不清楚。ADAR基因很可能是从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，APOBEC蛋白。这些蛋白最近被认为除了在HIV限制中发挥作用外，还可能在HIV进化和免疫逃避中发挥作用。我们的假设是，ADAR蛋白也被HIV使用，不仅用于调节，还用于进化和免疫逃避。因此，我们建议启动研究，系统和广泛地分析ADAR对艾滋病毒的影响。首先，我们将确定ADAR如何编辑HIV mRNAs中的茎区域，以及这与RNA运输途径有何关系。其次，我们将以治疗性HIV反义RNA为模型，分析HIV正义/反义RNA杂交物的ADAR编辑。具体目的1：分析ADAR1和ADAR2如何作用于编辑HIV mRNAs中的茎环区域，以及是否根据mRNA输出途径发生差异编辑。特定目的2：分析ADAR如何影响反义RNA介导的抑制和HIV反义靶区的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.