Department of Virology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
PRESTO, Japan Science and Technology Agency (JST), Kawaguchi, Japan.
Cell Commun Signal. 2022 Jun 21;20(1):95. doi: 10.1186/s12964-022-00902-7.
Viruses must adapt to the environment of their host cells to establish infection and persist. Diverse mammalian cells, including virus-infected cells, release extracellular vesicles such as exosomes containing proteins and miRNAs, and use these vesicles to mediate intercellular communication. However, the roles of exosomes in viral infection remain unclear.
We screened viral proteins to identify those responsible for the exosome-mediated enhancement of Epstein-Barr virus (EBV) infection. We identified BGLF2 protein encapsulated in exosomes, which were released by EBV-infected cells. BGLF2 protein is a tegument protein that exists in the space between the envelope and nucleocapsid, and it is released into the cytoplasm shortly after infection. BGLF2 protein-containing exosomes enhanced viral gene expression and repressed innate immunity, thereby supporting the EBV infection.
The EBV tegument protein BGLF2 is encapsulated in exosomes and released by infected cells to facilitate the establishment of EBV infection. These findings suggest that tegument proteins support viral infection not only between the envelope and nucleocapsid, as well as in extraviral particles such as exosomes. Video abstract.
病毒必须适应宿主细胞的环境才能建立感染并持续存在。包括病毒感染细胞在内的各种哺乳动物细胞会释放含有蛋白质和 miRNA 的细胞外囊泡（如外泌体），并利用这些囊泡来介导细胞间的通讯。然而，外泌体在病毒感染中的作用尚不清楚。
我们筛选了病毒蛋白，以鉴定那些负责外泌体介导增强 Epstein-Barr 病毒（EBV）感染的蛋白。我们鉴定出了 EBV 感染细胞释放的囊泡中的 BGLF2 蛋白。BGLF2 蛋白是一种位于包膜和核衣壳之间的被膜蛋白，在感染后不久就会被释放到细胞质中。含有 BGLF2 蛋白的外泌体增强了病毒基因的表达，并抑制了先天免疫，从而支持 EBV 的感染。
EBV 被膜蛋白 BGLF2 被包裹在囊泡中，并由感染细胞释放，以促进 EBV 感染的建立。这些发现表明，被膜蛋白不仅在包膜和核衣壳之间，而且在病毒外粒子（如外泌体）中支持病毒感染。视频摘要。
