Xie Baode, Calabro Valerie, Wainberg Mark A, Frankel Alan D
Department of Biochemistry and Biophysics, University of California, San Francisco, San Francisco, California 94143-2280, USA.
J Virol. 2004 Feb;78(3):1456-63. doi: 10.1128/jvi.78.3.1456-1463.2004.
The interaction between the arginine-rich motif (ARM) of the human immunodeficiency virus (HIV) Tat protein and TAR RNA is essential for Tat activation and viral replication. Two related lentiviruses, bovine immunodeficiency virus (BIV) and Jembrana disease virus (JDV), also require Tat ARM-TAR interactions to mediate activation, but the viruses have evolved different RNA-binding strategies. Interestingly, the JDV ARM can act as a "chameleon," adopting both the HIV and BIV TAR binding modes. To examine how RNA-protein interactions may evolve in a viral context and possibly to identify peptides that recognize HIV TAR in novel ways, we devised a retroviral system based on HIV replication to amplify and select for RNA binders. We constructed a combinatorial peptide library based on the BIV Tat ARM and identified peptides that, like the JDV Tat ARM, also function through HIV TAR, revealing unexpected sequence characteristics of an RNA-binding chameleon. The results suggest that a retroviral screening approach may help identify high-affinity TAR binders and may provide new insights into the evolution of RNA-protein interactions.
人类免疫缺陷病毒（HIV）Tat蛋白富含精氨酸的基序（ARM）与TAR RNA之间的相互作用对于Tat激活和病毒复制至关重要。两种相关的慢病毒，牛免疫缺陷病毒（BIV）和杰姆布兰纳病病毒（JDV），也需要Tat ARM-TAR相互作用来介导激活，但这两种病毒已经进化出不同的RNA结合策略。有趣的是，JDV的ARM可以充当“变色龙”，采用HIV和BIV的TAR结合模式。为了研究RNA-蛋白质相互作用在病毒环境中如何进化，并有可能识别以新方式识别HIV TAR的肽，我们设计了一种基于HIV复制的逆转录病毒系统，用于扩增和筛选RNA结合剂。我们基于BIV Tat ARM构建了一个组合肽库，并鉴定出了与JDV Tat ARM一样也通过HIV TAR发挥作用的肽，揭示了RNA结合变色龙意想不到的序列特征。结果表明，逆转录病毒筛选方法可能有助于识别高亲和力的TAR结合剂，并可能为RNA-蛋白质相互作用的进化提供新的见解。
