Regulation of HIV-1 RNA Splicing

描述（由申请人提供）：我们的长期目标是了解HIV-1如何调节其基因产物的水平以优化病毒复制。优化HIV-1基因表达的方法之一是通过选择性RNA剪接，这是产生适当水平的不同HIV-1 mRNA所必需的过程。干扰HIV-1可变剪接可能是一种新的抗病毒治疗方法。基本的HIV-1剪接模式在所有HIV-1毒株中是保守的，这表明其对病毒复制的重要性。使用不同剪接位点的效率由剪接位点本身和基因组内称为外显子剪接沉默子（ESS）和外显子剪接增强子（ESE）的顺式元件决定。我们最近的研究结果表明，一些元素对病毒复制至关重要，这推动了拟议的研究。首先，我们将在剪接位点和剪接元件内产生额外的突变，并研究它们在确定病毒Vif蛋白表达水平和病毒复制中的作用，Vif蛋白是一种作用于抗病毒细胞蛋白APOBEC 3G的蛋白质。第二，我们将分离新生的HIV-1 mRNA，以确定剪接发生在病毒mRNA生命周期的哪一点-是在RNA转录完成期间还是之后。最后，我们将研究与主要M组毒株相比，O组离群病毒的剪接调节。O组病毒似乎使用与M组HIV-1毒株不同的顺式元件来调节剪接。这些元素的鉴定可能会给我们关于HIV-1进化的新见解。

DESCRIPTION (provided by applicant): Our long range objective is to understand how HIV-1 regulates the levels of its gene products to optimize virus replication. One of the ways gene expression of HIV-1 is optimized is through alternative RNA splicing, a process which is necessary to produce the appropriate levels of the different HIV-1 mRNAs . Interference with HIV-1 alternative splicing may be a novel approach for antiviral therapy. The basic HIV-1 splicing pattern is conserved in all strains of HIV-1 suggesting its importance for viral replication. The efficiencies with which different splice sites are used are determined by the splice sites themselves and cis elements within the genome called exonic splicing silencers (ESS) and exonic splicing enhancers (ESE). The proposed studies are driven by our recent results indicating the crucial importance of some of the elements for virus replication. First, we will create additional mutations within splice sites and splicing elements and study their role in determining the level of expression of the viral Vif protein, a protein which acts to inactivate the antiviral cellular protein APOBEC3G, and in virus replication. Second, we will isolate nascent HIV-1 mRNA to determine at what point in the lifetime of the viral mRNA that splicing takes place-whether it is during or after RNA transcription is completed. Finally, we will study regulation of splicing of the outlier Group O viruses compared to the major Group M strains. Group O viruses appear to use different cis elements than Group M HIV-1 strains to regulate splicing. Identification of these elements may give us new insights about the evolution of HIV-1.