Versatility of the accessory C proteins of Sendai virus: Contribution to virus assembly as an additional role
Versatility of the accessory C proteins of Sendai virus: Contribution to virus assembly as an additional role
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DOI：
10.1128/jvi.74.12.5619-5628.2000
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发表时间：
2000-06-01
影响因子：
5.4
通讯作者：
Yoshiyuki, N
中科院分区：
文献类型：
--
作者：
Hasan, MK;Kato, A;Yoshiyuki, N
仙台病毒（SeV）的P/C mRNA使用相对于磷酸（P）蛋白的开放阅读框的+1框和不同位置的起始密码子编码一套嵌套的辅助蛋白C '、C、Y1和Y2，统称为C蛋白。C蛋白似乎基本上是非结构蛋白，因为它们在感染细胞中大量存在，但在病毒体中的代表性大大不足。我们先前创建了4C（-）SeV，其不表达四种C蛋白中的任何一种，并得出结论，C蛋白是绝对非必需的基因产物，但极大地促进了病毒的完全复制和感染性（A. Kurotani等，Genes Cells 3：111-124，1998）。在此，我们进一步表征了培养细胞中的4C（-）病毒增殖。相对于亲本野生型（WT）SeV，突变病毒的病毒蛋白和mRNA合成增强。然而，病毒产量大大降低，此外，4C（-）病毒粒子在蔗糖梯度中的大小、形状和沉降特征似乎高度异常，并且表现出感染性与血凝单位的比率显著低于WT。在WT感染的细胞中，C蛋白似乎与基质（M）蛋白几乎完全共定位，与外部包膜糖蛋白（血凝素-神经氨酸酶[HN]）共定位非常好，与内部P蛋白共定位非常差。在不存在C蛋白的情况下，M蛋白以及包膜蛋白HN和融合（F）蛋白掺入子代病毒体中有显著延迟。这些结果强烈表明，辅助和基本上非结构的C蛋白是至关重要的SeV组装过程中所需的。进一步发现C蛋白的这种作用独立于它们最近发现的抵消干扰素-α/β的抗病毒作用的功能。因此，SeV C蛋白似乎是相当通用的。
The P/C mRNA of Sendai virus (SeV) encodes a nested set of accessory proteins, C', C, Y1, and Y2, referred to collectively as C proteins, using the +1 frame relative to the open reading frame of phospho (P) protein and initiation codons at different positions. The C proteins appear to be basically nonstructural proteins as they are found abundantly in infected cells but greatly underrepresented in the virions. We previously created a 4C(-) SeV, which expresses none of the four C proteins, and concluded that the C proteins are categorically nonessential gene products but greatly contribute to viral full replication and infectivity (A. Kurotani et al,, Genes Cells 3:111-124, 1998), Here, we further characterized the 4C(-) virus multiplication in cultured cells. The viral protein and mRNA synthesis was enhanced with the mutant virus relative to the parental wild-type (WT) SeV. However, the viral yields were greatly reduced, in addition, the 4C(-) virions appeared to be highly anomalous in size, shape, and sedimentation profile in a sucrose gradient and exhibited the ratios of infectivity to hemagglutination units significantly lower than those of the WT. In the WT infected cells, C proteins appeared to colocalize almost perfectly with the matrix (M) proteins, pretty well with an external envelope glycoprotein (hemagglutinin-neuraminidase [HN]), and very poorly with the internal P protein. In the absence of C proteins, there was a significant delay of the incorporation of M protein and both of the envelope proteins, HN and fusion (F) proteins, into progeny virions. These results strongly suggest that the accessory and basically nonstructural C proteins are critically required in the SeV assembly process. This role of C proteins was further found to be independent of their recently discovered function to counteract the antiviral action of interferon-alpha/beta. SeV C proteins thus appear to be quite versatile.