Influenza C and D Viruses Package Eight Organized Ribonucleoprotein Complexes
Influenza C and D Viruses Package Eight Organized Ribonucleoprotein Complexes
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DOI：
10.1128/jvi.02084-17
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发表时间：
2018-03-01
影响因子：
5.4
通讯作者：
Kawaoka, Yoshihiro
中科院分区：
文献类型：
--
作者：
Nakatsu, Sumiho;Murakami, Shin;Kawaoka, Yoshihiro
甲型和乙型流感病毒有八个片段的单链负义RNA基因组，而丙型和丁型流感病毒有七个片段的基因组。每个基因组RNA片段都以核糖核蛋白复合体(RNP)的形式存在，与核蛋白和病毒粒子中依赖RNA的RNA聚合酶结合在一起。D型流感病毒是最近从猪和牛身上分离出来的，但其形态还没有得到充分的研究。在这里，我们研究了D/bovine/Yamagata/10710/2016(D/Yamagata)和C/Ann Arbor/50(C/AA)的形态特征，重点是包装在病毒粒子中的RNP。通过扫描电子显微镜断层扫描，我们发现超过70%的D/Yamagata和C/AA病毒粒子包装了8个RNPs，它们与甲型和乙型流感病毒一样，以“1+7”的模式排列，尽管C和D型病毒基因组只有7个片段。这些结果表明，无论基因组中有多少个RNA片段，流感病毒一般都会包装8个RNPs，这些RNPs以“1+7”的方式排列。为了使子代病毒粒子具有感染性，每个病毒粒子需要包装它们的所有基因组片段。一些研究支持这一结论，即甲型和乙型流感病毒选择性地包装了八个不同的基因组RNA片段；然而，拥有七个片段基因组的流感C和D病毒的包装却鲜为人知。通过使用电子显微镜，我们发现C型和D型流感病毒和A型和B型流感病毒一样，包装了8个RNA片段。这些结果表明，流感病毒更喜欢将8个RNA片段包装在病毒粒子中，而不是基因组片段的数量。
Influenza A and B viruses have eight-segmented, single-stranded, negative-sense RNA genomes, whereas influenza C and D viruses have seven-segmented genomes. Each genomic RNA segment exists in the form of a ribonucleoprotein complex (RNP) in association with nucleoproteins and an RNA-dependent RNA polymerase in virions. Influenza D virus was recently isolated from swine and cattle, but its morphology is not fully studied. Here, we examined the morphological characteristics of D/bovine/Yamagata/10710/2016 (D/Yamagata) and C/Ann Arbor/50 (C/AA), focusing on RNPs packaged within the virions. By scanning transmission electron microscopic tomography, we found that more than 70% of D/Yamagata and C/AA virions packaged eight RNPs arranged in the "1 + 7" pattern as observed in influenza A and B viruses, even though type C and D virus genomes are segmented into only seven segments. These results imply that influenza viruses generally package eight RNPs arranged in the "1 + 7" pattern regardless of the number of RNA segments in their genome.IMPORTANCE The genomes of influenza A and B viruses are segmented into eight segments of negative-sense RNA, and those of influenza C and D viruses are segmented into seven segments. For progeny virions to be infectious, each virion needs to package all of their genomic segments. Several studies support the conclusion that influenza A and B viruses selectively package eight distinct genomic RNA segments; however, the packaging of influenza C and D viruses, which possess seven segmented genomes, is less understood. By using electron microscopy, we showed that influenza C and D viruses package eight RNA segments just as influenza A and B viruses do. These results suggest that influenza viruses prefer to package eight RNA segments within virions independent of the number of genome segments.