Herpes Simplex Virus 1 Protein UL37 Interacts with Viral Glycoprotein gK and Membrane Protein UL20 and Functions in Cytoplasmic Virion Envelopment
Herpes Simplex Virus 1 Protein UL37 Interacts with Viral Glycoprotein gK and Membrane Protein UL20 and Functions in Cytoplasmic Virion Envelopment
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DOI：
10.1128/jvi.00278-14
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发表时间：
2014-06-01
影响因子：
5.4
通讯作者：
Kousoulas, Konstantin G.
中科院分区：
文献类型：
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作者：
Jambunathan, Nithya;Chouljenko, Dmitry;Kousoulas, Konstantin G.
我们已经证明，糖蛋白 K (gK) 及其相互作用伙伴 UL20 蛋白在病毒粒子包膜中发挥着至关重要的作用。具体来说，缺乏 gK 或 UL20 的病毒体无法获得包膜，从而导致衣壳在受感染细胞的细胞质中积聚。单纯疱疹病毒 1 (HSV-1) UL37 蛋白也与细胞质病毒粒子包膜有关。为了进一步研究 UL37 在病毒粒子包膜中的作用，通过在 UL37 氨基酸序列中紧接氨基酸 480 后插入 12 个氨基酸的蛋白 C (protC) 表位标签构建了重组病毒 DC480。通过蛋白质免疫印迹中的抗 protC 抗体检测，DC480 突变病毒表达全尺寸 UL37，在感染细胞的细胞质中积累了无包膜的衣壳，并在非洲绿猴肾 (Vero) 细胞上产生非常小的斑块，其大小与 UL20 无效和 UL37 无效病毒产生的斑块大小相似。当在 Vero 细胞上生长时，DC480 病毒的复制效率比亲代野生型病毒低近 4 个对数级。然而，当病毒在表达 UL20 基因的 FRT 细胞上生长时，与 Vero 细胞上的滴度相比，DC480 突变病毒滴度增加了近 20 倍，而 UL37 无效病毒在 FRT 细胞上的复制效率比 DC480 病毒低约 20 倍。免疫共沉淀实验和邻近连接测定表明，gK 和 UL20 与感染细胞中的 UL37 蛋白相互作用。总的来说，这些结果表明 UL37 与 gK-UL20 蛋白复合物相互作用，促进细胞质病毒颗粒包封。
We have shown that glycoprotein K (gK) and its interacting partner, the UL20 protein, play crucial roles in virion envelopment. Specifically, virions lacking either gK or UL20 fail to acquire an envelope, thus causing accumulation of capsids in the cytoplasm of infected cells. The herpes simplex virus 1 (HSV-1) UL37 protein has also been implicated in cytoplasmic virion envelopment. To further investigate the role of UL37 in virion envelopment, the recombinant virus DC480 was constructed by insertion of a 12-amino-acid protein C (protC) epitope tag within the UL37 amino acid sequence immediately after amino acid 480. The DC480 mutant virus expressed full-size UL37 as detected by the anti-protC antibody in Western immunoblots, accumulated unenveloped capsids in the cytoplasm of infected cells, and produced very small plaques on African green monkey kidney (Vero) cells that were similar in size to those produced by the UL20-null and UL37-null viruses. The DC480 virus replicated nearly 4 log less efficiently than the parental wild-type virus when grown on Vero cells. However, DC480 mutant virus titers increased nearly 20-fold when the virus was grown on FRT cells engineered to express the UL20 gene in comparison to the titers on Vero cells, while the UL37-null virus replicated approximately 20-fold less efficiently than the DC480 virus on FRT cells. Coimmunoprecipitation experiments and proximity ligation assays showed that gK and UL20 interact with the UL37 protein in infected cells. Collectively, these results indicate that UL37 interacts with the gK-UL20 protein complex to facilitate cytoplasmic virion envelopment.