The small envelope protein E is not essential for murine coronavirus replication
The small envelope protein E is not essential for murine coronavirus replication
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DOI：
10.1128/jvi.77.8.4597-4608.2003
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发表时间：
2003-04-01
影响因子：
5.4
通讯作者：
Masters, PS
中科院分区：
文献类型：
--
作者：
Kuo, LL;Masters, PS
几项研究已经证明了小包膜(E)蛋白在冠状病毒组装中的重要性。虽然其确切的功能没有明确的定义，但E在病毒粒子被膜的形态发生中起着关键的作用。E蛋白的单独表达导致其整合到从细胞释放的小泡中，E蛋白与膜蛋白M的共同表达导致冠状病毒样颗粒的组装。我们之前已经产生了小鼠肝炎病毒(MHV)的E基因突变体，这些突变体在病毒生长方面存在明显的缺陷，并产生了与轻型型病毒粒子相比被异常组装的病毒粒子。我们现在已经能够获得一个活的MHV突变体，在该突变体中，整个E基因以及非必需的上游基因4和5a已经被删除。这个突变体(DeltaE)是通过靶向RNA重组方法获得的，该方法利用了一个强大的基于宿主范围的选择系统。与野生型MHV形成的斑块相比，DeltaE突变体产生的斑块具有不寻常的形态。尽管DeltaE突变体的生长速度和感染性滴度都很低，但它在遗传上是稳定的，在几代后没有表现出可检测到的表型变化。该突变体的特性进一步支持了E蛋白在MHV复制中的重要性，但令人惊讶的是，它们也表明E蛋白不是必需的。
The importance of the small envelope (E) protein in the assembly of coronaviruses has been demonstrated in several studies. While its precise function is not clearly defined, E is a pivotal player in the morphogenesis of the virion envelope. Expression of the E protein alone results in its incorporation into vesicles that are released from cells, and the coexpression of the E protein with the membrane protein M leads to the assembly of coronavirus-like particles. We have previously generated E gene mutants of mouse hepatitis virus (MHV) that had marked defects in viral growth and produced virions that were aberrantly assembled in comparison to mild-type virions. We have now been able to obtain a viable MHV mutant in which the entire E gene, as well as the nonessential upstream genes 4 and 5a, has been deleted. This mutant (DeltaE) was obtained by a targeted RNA recombination method that makes use of a powerful host range-based selection system. The DeltaE mutant produces tiny plaques with an unusual morphology compared to plaques formed by wild-type MHV. Despite its low growth rate and low infectious titer, the DeltaE mutant is genetically stable, showing no detectable phenotypic changes after several passages. The properties of this mutant provide further support for the importance of E protein in MHV replication, but surprisingly, they also show that E protein is not essential.