Graduate School of Infectious Diseases, Hokkaido University, Sapporo, 060-8638, Japan.
Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo, 060-8638, Japan.
Sci Rep. 2021 Nov 26;11(1):22977. doi: 10.1038/s41598-021-01985-x.
Severe fever with thrombocytopenia syndrome virus (SFTSV) is an emerging bunyavirus that causes novel zoonotic diseases in Asian countries including China, Japan, South Korea, and Vietnam. In phleboviruses, viral proteins play a critical role in viral particle formation inside the host cells. Viral glycoproteins (GPs) and RNA-dependent RNA polymerase (RdRp) are colocalized in the Golgi apparatus and endoplasmic reticulum-Golgi intermediate compartment (ERGIC). The nucleocapsid (N) protein was widely expressed in the cytoplasm, even in cells coexpressing GP. However, the role of SFTSV N protein remains unclear. The subcellular localization of SFTSV structural proteins was investigated using a confocal microscope. Subsequently, minigenome and immunoprecipitation assays were carried out. The N protein interacts with viral RNA (vRNA) and further shows translational activity with RdRp which is L protein and localized in the ERGIC and Golgi apparatus when co-expressed with GP. On the other hand, mutant N protein did not interact with vRNA either localized in the ERGIC or Golgi apparatus. The interaction between the N protein of SFTSV and vRNA is important for the localization of viral proteins and viral assembly. This study provides useful insights into the life cycle of SFTSV, which will lead to the detection of antiviral targets.
严重发热伴血小板减少综合征病毒（SFTSV）是一种新兴的布尼亚病毒，在中国、日本、韩国和越南等亚洲国家引起新型人畜共患病。在黄病毒属中，病毒蛋白在宿主细胞内病毒粒子的形成中起着关键作用。病毒糖蛋白（GP）和 RNA 依赖性 RNA 聚合酶（RdRp）在高尔基体和内质网-高尔基体中间区室（ERGIC）中共定位。核衣壳（N）蛋白在细胞质中广泛表达，即使在共表达 GP 的细胞中也是如此。然而，SFTSV N 蛋白的作用仍不清楚。使用共聚焦显微镜研究了 SFTSV 结构蛋白的亚细胞定位。随后进行了小基因组和免疫沉淀测定。N 蛋白与病毒 RNA（vRNA）相互作用，并与 RdRp 进一步显示翻译活性，当与 GP 共表达时，RdRp 定位于 ERGIC 和高尔基体。另一方面，突变的 N 蛋白既不与 vRNA 相互作用，也不定位在 ERGIC 或高尔基体中。SFTSV 的 N 蛋白与 vRNA 之间的相互作用对于病毒蛋白的定位和病毒组装很重要。本研究为 SFTSV 的生命周期提供了有用的见解，这将有助于发现抗病毒靶点。
