中文摘要：甜瓜坏死斑点病毒（MNSV）外壳蛋白（CP）由三个主要的结构域组成。中间的S端结构域在病毒基因组周围建立了强固的蛋白质外壳，而C端凸域或P结构域则参与了病毒粒子向传输载体的附着。本研究发现，N端结构域或R结构域以及连接N结构域和S结构域的臂区参与了病毒周期不同的关键环节，如细胞到细胞之间的运动、RNA沉默抑制以及发病机制。研究结果表明，R结构域和MNSV CP臂区除了基因组结合和包装等基本功能外，还可以通过阻止小RNA系统性传播来抑制RNA沉默。
外文摘要：The coat protein (CP) of Melon necrotic spot virus (MNSV) is structurally composed of three major domains. The middle S-domain builds a robust protein shell around the viral genome, whereas the C-terminal protruding domain, or P-domain, is involved in the attachment of virions to the transmission vector. Here, we have shown that the N-terminal domain, or R-domain, and the arm region, which connects the R-domain and S-domain, are involved in different key steps of the viral cycle, such as cell-to-cell movement and the suppression of RNA silencing and pathogenesis through their RNA-binding capabilities. Deletion mutants revealed that the CP RNA-binding ability was abolished only after complete, but not partial, deletion of the R-domain and the arm region. However, a comparison of the apparent dissociation constants for the CP RNA-binding reaction of several partial deletion mutants showed that the arm region played a more relevant role than the R-domain in in vitro RNA binding. Similar results were obtained in in vivo assays, although, in this case, full-length CPs were required to encapsidate full-length genomes. We also found that the R-domain carboxyl portion and the arm region were essential for efficient cell-to-cell movement, for enhancement of Potato virus X pathogenicity, for suppression of systemic RNA silencing and for binding of small RNAs. Therefore, unlike other carmovirus CPs, the R-domain and the arm region of MNSV CP have acquired, in addition to other essential functions such as genome binding and encapsidation functions, the ability to suppress RNA silencing by preventing systemic small RNA transport.
外文关键词：coat protein; plant virus; RNA binding; silencing
作者：Serra-Soriano, Marta; Antonio Navarro, Jose; Pallas, Vicente
作者单位：瓦伦西亚大学
期刊名称：MOLECULAR PLANT PATHOLOGY
期刊影响因子：4.45
出版年份：2017
出版刊次：8
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