Glycoprotein B cleavage is important for murid herpesvirus 4 to infect myeloid cells.
Glycoprotein B cleavage is important for murid herpesvirus 4 to infect myeloid cells.
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DOI：
10.1128/jvi.00709-13
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发表时间：
2013-10
影响因子：
5.4
通讯作者：
Stevenson PG
中科院分区：
文献类型：
--
作者：
Glauser DL;Milho R;Frederico B;May JS;Kratz AS;Gillet L;Stevenson PG
糖蛋白B（gB）是疱疹病毒膜融合过程中的一种保守的病毒颗粒组分。与许多（但不是所有）疱疹病毒一样，鼠疱疹病毒4型（MuHV-4）的gB被切割成二硫键连接的亚基，显然是通过弗林蛋白酶。阻止某些疱疹病毒的gB裂解在体外引起轻微的感染缺陷，但裂解对宿主定植的贡献尚不清楚。为了解决这个问题，我们突变了MuHV-4 gB的弗林蛋白酶切割位点（R-R-K-R）。废除gB切割不影响其表达水平，糖基化，或抗原构象。在体外，突变病毒正常进入成纤维细胞和上皮细胞，但在骨髓细胞，如巨噬细胞和骨髓来源的树突状细胞有显着的进入缺陷。在骨髓细胞中的赤字是不是由于减少病毒粒子结合或内吞作用，这表明gB裂解促进感染在postendocytic进入步骤，大概是病毒膜融合。在体内，缺乏gB裂解的病毒在肺中的裂解扩散减少。肺泡上皮细胞感染正常，但肺泡巨噬细胞感染明显减少。尽管如此，在淋巴组织中建立了正常的长期潜伏期。
Glycoprotein B (gB) is a conserved herpesvirus virion component implicated in membrane fusion. As with many—but not all—herpesviruses, the gB of murid herpesvirus 4 (MuHV-4) is cleaved into disulfide-linked subunits, apparently by furin. Preventing gB cleavage for some herpesviruses causes minor infection deficits in vitro, but what the cleavage contributes to host colonization has been unclear. To address this, we mutated the furin cleavage site (R-R-K-R) of the MuHV-4 gB. Abolishing gB cleavage did not affect its expression levels, glycosylation, or antigenic conformation. In vitro, mutant viruses entered fibroblasts and epithelial cells normally but had a significant entry deficit in myeloid cells such as macrophages and bone marrow-derived dendritic cells. The deficit in myeloid cells was not due to reduced virion binding or endocytosis, suggesting that gB cleavage promotes infection at a postendocytic entry step, presumably viral membrane fusion. In vivo, viruses lacking gB cleavage showed reduced lytic spread in the lungs. Alveolar epithelial cell infection was normal, but alveolar macrophage infection was significantly reduced. Normal long-term latency in lymphoid tissue was established nonetheless.