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A型流行性感冒病毒的负链RNA基因组由编码病毒中12个蛋白质的八个节段组成。在病毒组装的最后阶段,病毒体从细胞顶端胞浆膜突出时将这些基因组的病毒体(v)RNAs吸收进其中。基因组分段赋予了流感病毒进化的优势,但也提出了问题,在病毒体组装时需要八个节段每一个的至少一个复制本以产生完全有传染性的病毒颗粒。历史上一直存在争论:一方赞同确保足额的基因组合并的特异性包装机制;另一方赞同基因组节段被随机选择而不是以充足数量被包装以确保能自行产生合理比例病毒体的替代模式。近年来人们对该问题已达成一致意见:大多数病毒体仅包含八个节段,特异性机制为选择每个vRNA的某一复制本的确发挥了作用。本综述总结了得出这一结论所做的工作,叙述了在识别特异性包装信号方面最新的进展,讨论了这些RNA元素运转的可能机制。
The negative-strand RNA genome of influenza type A virus consists of eight segments that encode 12 proteins in the virus. During the final stages of virus assembly, virions (v) RNAs of these genomes are absorbed into the virion as they protrude from the cytoplasmic membrane of the apical cell. The genomic segment confers the advantage of the evolution of the influenza virus, but also raises the question of requiring at least one replica of each of the eight segments at virion assembly to produce a fully infectious virus particle. There has been a long history of controversy: one favors specific packaging mechanisms that ensure adequate genome pooling; the other favors alternative patterns where genome segments are randomly selected rather than being packed in sufficient quantities to ensure that they produce a reasonable proportion of virions on their own. There has been agreement on this issue in recent years that most virosomes contain only eight segments and that the specific mechanism does play a role in selecting a certain copy of each vRNA. This review summarizes the work done to arrive at this conclusion, describes the recent advances in identifying specific packaging signals and discusses the possible mechanisms by which these RNA elements operate.