A型流感病毒的基因组包装

Genome packaging of influenza A virus

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-sense RNA genome of influenza A virus is composed of eight segments, which encode 12 pro- teins between them. At the final stage of viral assembly, these genomic virion （v）RNAs are incorporated into the virion as it buds from the apical plasma membrane of the cell. Genome segmentation confers evolutionary advantages on the virus, but also poses a problem during virion assembly as at least one copy of each of the eight segments is required to produce a fully infec- tious virus particle. Historically, arguments have been presented in favour of a specific packaging mechanism that ensures in- corporation of a full genome complement, as well as for an alternative model in which segments are chosen at random but pack- aged in sufficient numbers to ensure that a reasonable proportion of virions are viable. The question has seen a resurgence of in- terest in recent years leading to a consensus that the vast majority of virions contain no more than eight segments and that a spe- cific mechanism does indeed function to select one copy of each vRNA. This review summarizes work leading to this conclusion. We reviewed recent progress in identifying the specific packaging signals and discussed possible mechanisms by which these RNA elements might operate.