Solution Structure of the HIV-1 Intron Splicing Silencer and Its Interactions with the UP1 Domain of Heterogeneous Nuclear Ribonucleoprotein (hnRNP) A1
Solution Structure of the HIV-1 Intron Splicing Silencer and Its Interactions with the UP1 Domain of Heterogeneous Nuclear Ribonucleoprotein (hnRNP) A1
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DOI：
10.1074/jbc.m115.674564
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发表时间：
2016-01-29
影响因子：
4.8
通讯作者：
Tolbert, Blanton S.
中科院分区：
文献类型：
--
作者：
Jain, Niyati;Morgan, Christopher E.;Tolbert, Blanton S.
人类免疫缺陷病毒1型(HIV-1)的剪接模式是通过招募拮抗宿主RNA结合蛋白的顺式调控元件来维持的。3‘受体A7的活性通过内含子剪接抑制子(ISS)、二段外显子剪接抑制子(ESS3a/b)和外显子剪接增强子(ESE3)组成的复杂网络受到严格调控。由于HIV-1的剪接依赖于蛋白质-RNA的相互作用，因此了解剪接位点周围的三级结构是很重要的。在这里，我们介绍了系统发育保守的ISS茎环的核磁共振溶液结构。ISS采用稳定的结构，由保守的UG摆动对、折叠的2X2(GU/UA)内环、UU凸起和灵活的AGUGA顶环组成。量热和生化滴定表明，异质核糖核蛋白A1的UP1结构域与ISS顶环结合--特异地并具有纳摩尔亲和力。总的来说，这项工作为HIV-1如何使用保守的RNA结构来征用宿主RNA结合蛋白提供了更多的见解。
Splicing patterns in human immunodeficiency virus type 1 (HIV-1) are maintained through cis regulatory elements that recruit antagonistic host RNA-binding proteins. The activity of the 3' acceptor site A7 is tightly regulated through a complex network of an intronic splicing silencer (ISS), a bipartite exonic splicing silencer (ESS3a/b), and an exonic splicing enhancer (ESE3). Because HIV-1 splicing depends on protein-RNA interactions, it is important to know the tertiary structures surrounding the splice sites. Herein, we present the NMR solution structure of the phylogenetically conserved ISS stem loop. ISS adopts a stable structure consisting of conserved UG wobble pairs, a folded 2X2 (GU/UA) internal loop, a UU bulge, and a flexible AGUGA apical loop. Calorimetric and biochemical titrations indicate that the UP1 domain of heterogeneous nuclear ribonucleoprotein A1 binds the ISS apical loop site-specifically and with nanomolar affinity. Collectively, this work provides additional insights into how HIV-1 uses a conserved RNA structure to commandeer a host RNA-binding protein.