School of Medicine, Hokkaido University, Sapporo 060-8638, Japan.
Department of Microbiology and Immunology, Faculty of Medicine, Hokkaido University, Sapporo 060-8638, Japan.
Viruses. 2020 Dec 27;13(1):33. doi: 10.3390/v13010033.
Severe fever with thrombocytopenia syndrome virus subclone B7 shows strong plaque formation and cytopathic effect induction compared with other subclones and the parental strain YG1. Compared to YG1 and the other subclones, only B7 possesses a single substitution in the L protein at the amino acid position 1891, in which N is changed to K (N1891K). In this study, we evaluate the effects of this mutation on L protein activity via a cell-based minigenome assay. Substitutions of N with basic amino acids (K or R) enhanced polymerase activity, while substitutions with an acidic amino acid (E) decreased this activity. Mutation to other neutral amino acids showed no significant effect on activity. These results suggest that the characteristic of the amino acid at position 1891 of the L protein are critical for its function, especially with respect to the charge status. Our data indicate that this C-terminal domain of the L protein may be crucial to its functions in genome transcription and viral replication.
严重发热伴血小板减少综合征病毒亚克隆 B7 与其他亚克隆和母株 YG1 相比，具有较强的斑块形成和致细胞病变效应。与 YG1 和其他亚克隆相比，只有 B7 在 L 蛋白的第 1891 位氨基酸处发生了单个取代，即 N 突变为 K（N1891K）。在这项研究中，我们通过基于细胞的小基因 组测定来评估该突变对 L 蛋白活性的影响。用碱性氨基酸（K 或 R）取代 N 增强了聚合酶活性，而用酸性氨基酸（E）取代则降低了该活性。用其他中性氨基酸取代则对活性没有显著影响。这些结果表明，L 蛋白第 1891 位氨基酸的特性对其功能至关重要，尤其是其电荷状态。我们的数据表明，L 蛋白的 C 末端结构域可能对其在基因组转录和病毒复制中的功能至关重要。
