中文摘要：水稻条纹病毒（RSV）是水稻上重要的病原菌。RSV基因组由4个单链RNA片段组成，这些单链RNA片段编码7个病毒蛋白。先前已有报道发现，NS3是RNA沉默和自相互作用的病毒抑制子。作者利用模型预测蛋白结构，鉴定氨基酸残留物和模体，包括4种NS3自交互作用所必需的α-螺旋模体。然后利用酵母双杂交（Y2H）系统和双分子荧光互补（BiFC）分析技术研究全长NS3、截短的NS3和丙氨酸置换突变体之间的交互作用。研究结果表明，RSV需要通过NS3自交互作用来抑制RNA沉默从而对抗宿主防御。
外文摘要：Rice stripe virus (RSV) is an important pathogen of rice. The RSV genome consists of four single-stranded RNA segments that encode seven viral proteins. A previous report found that NS3 is a viral suppressor of RNA silencing and self interacts. Using a model that predicts protein structure, we identified amino acid residues or motifs, including four α-helix motifs, required for NS3 self-interaction. We then used yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays to study the interactions between full-length NS3 and its truncated and alanine substitution mutants. Y2H and BiFC results showed that the N-terminal region of NS3 is essential for self-interaction. All a-helix deletion mutants and substitution mutants lost the ability to self interact. To identify the relationship between NS3 self-interaction and silencing suppressor activity, we used a GFP silencing system in Nicotiana benthamiana with Agrobacterium-mediated transient overexpression of each mutated NS3 protein. All of the deletion and the a-helix substitution mutants that had lost the ability to self interact also lost their silencing suppressor ability. The substitution of amino acids with alanine at positions 70-75, 76-83, and 173-177, however, resulted in mutants that were able to self-interact but were unable to function as silencing suppressors. These results suggest that RSV requires NS3 self-interaction to suppress RNA silencing and to thereby counter host defenses.
外文关键词：Rice stripe virus; Protein 3D structure prediction; RNA silencing; Viral suppressor of RNA silencing; Protein-protein interaction; GFP silencing
作者：Kim, Hangil; Cho, Won Kyong; Lian, Sen; 等
作者单位：首尔大学
期刊名称：VIRUS RESEARCH
期刊影响因子：2.55
出版年份：2017
出版刊次：5
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