Cucumber necrosis virus (CNV) is a T = 3 icosahedral virus with a (+)ssRNA genome. The N-terminal CNV coat protein arm contains a conserved, highly basic sequence (“KGRKPR”), which we postulate is involved in RNA encapsidation during virion assembly. Seven mutants were constructed by altering the CNV “KGRKPR” sequence; the four basic residues were mutated to alanine individually, in pairs, or in total. Virion accumulation and vRNA encapsidation were significantly reduced in mutants containing two or four substitutions and virion morphology was also affected, where both T = 1 and intermediate-sized particles were produced. Mutants with two or four substitutions encapsidated significantly greater levels of truncated RNA than that of WT, suggesting that basic residues in the “KGRKPR” sequence are important for encapsidation of full-length CNV RNA. Interestingly, “KGRKPR” mutants also encapsidated relatively higher levels of host RNA, suggesting that the “KGRKPR” sequence also contributes to selective encapsidation of CNV RNA.

黄瓜坏死病毒（CNV）是具有（+）ssRNA基因组的T = 3二十面体病毒。N末端CNV外壳蛋白臂包含一个保守的高碱性序列（“ KGRKPR”），我们假定该序列与病毒体组装过程中的RNA衣壳化有关。通过改变CNV“ KGRKPR”序列，构建了七个突变体。这四个碱性残基分别，成对或全部突变为丙氨酸。在含有两个或四个取代的突变体中，病毒粒子的积累和vRNA的衣壳化显着降低，并且病毒粒子的形态也受到影响，其中T均为1，中等大小。与WT相比，具有两个或四个取代的突变体使截短的RNA的水平明显更高，这表明“ KGRKPR”序列中的碱性残基对于全长CNV RNA的壳体化很重要。有趣的是，