College of Life Science, Northeast Forestry University, Harbin 150040, People's Republic of China.
State Key Laboratory for Animal Disease Control and Prevention & National Data Center for Animal Infectious Diseases, Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150069, People's Republic of China.
Int J Biol Macromol. 2024 Apr;265(Pt 1):130847. doi: 10.1016/j.ijbiomac.2024.130847. Epub 2024 Mar 13.
Getah virus (GETV) belongs to the Alphavirus genus in the Togaviridae family and is a zoonotic arbovirus causing disease in both humans and animals. The capsid protein (CP) of GETV regulates the viral core assembly, but the mechanism underlying this process is poorly understood. In this study, we demonstrate that CP undergoes liquid-liquid phase separation (LLPS) with the GETV genome RNA (gRNA) in vitro and forms cytoplasmic puncta in cells. Two regions of GETV gRNA (nucleotides 1-4000 and 5000-8000) enhance CP droplet formation in vitro and the lysine-rich Link region of CP is essential for its phase separation. CP(K/R) mutant with all lysines in the Link region replaced by arginines exhibits improved LLPS versus wild type (WT) CP, but CP(K/E) mutant with lysines substituted by glutamic acids virtually loses condensation ability. Consistently, recombinant virus mutant with CP(K/R) possesses significantly higher gRNA binding affinity, virion assembly efficiency and infectivity than the virus with WT-CP. Overall, our findings provide new insights into the understanding of GETV assembly and development of new antiviral drugs against alphaviruses.
基孔肯雅病毒（GETV）属于黄病毒科中的甲病毒属，是一种人畜共患的虫媒病毒，可引起人类和动物疾病。GETV 的衣壳蛋白（CP）调节病毒核心的组装，但该过程的机制尚不清楚。在这项研究中，我们证明 CP 与 GETV 基因组 RNA（gRNA）在体外发生液-液相分离（LLPS），并在细胞中形成细胞质斑点。GETV gRNA 的两个区域（核苷酸 1-4000 和 5000-8000）增强 CP 液滴的形成，CP 的富含赖氨酸的 Link 区对于其相分离是必需的。Link 区中的所有赖氨酸都被精氨酸取代的 CP(K/R)突变体与野生型（WT）CP 相比表现出更好的 LLPS，但赖氨酸被谷氨酸取代的 CP(K/E)突变体几乎失去了浓缩能力。一致地，与具有 WT-CP 的病毒相比，携带 CP(K/R)的重组病毒突变体具有更高的 gRNA 结合亲和力、病毒粒子组装效率和感染性。总体而言，我们的发现为理解 GETV 组装提供了新的见解，并为开发针对甲病毒的新抗病毒药物提供了思路。
