Department of Biochemistry, Genetics and Microbiology, University of Pretoria, Hatfield 0083, South Africa.
Viruses. 2022 Jul 26;14(8):1624. doi: 10.3390/v14081624.
A unique characteristic of the African horse sickness virus (AHSV) major core protein VP7 is that it is highly insoluble, and spontaneously forms crystalline particles in AHSV-infected cells and when expressed in vitro. The aggregation of AHSV VP7 into these crystals presents many problems in AHSV vaccine development, and it is unclear whether VP7 aggregation affects AHSV assembly or contributes to AHSV pathogenesis. Here, we set out to abolish VP7 self-assembly by targeting candidate amino acid regions on the surface of the VP7 trimer via site-directed mutagenesis. It was found that the substitution of seven amino acids resulted in the complete disruption of AHSV VP7 self-assembly, which abolished the formation of VP7 crystalline particles and converted VP7 to a fully soluble protein still capable of interacting with VP3 to form core-like particles. This work provides further insight into the formation of AHSV VP7 crystalline particles and the successful development of AHSV vaccines. It also paves the way for future research by drawing comparisons with similar viral phenomena observed in human virology.
非洲马瘟病毒（AHSV）主要核心蛋白 VP7 的一个独特特征是其高度不溶，并且在 AHSV 感染的细胞中和体外表达时会自发形成结晶颗粒。AHSV VP7 聚集成这些晶体在 AHSV 疫苗开发中带来了许多问题，目前尚不清楚 VP7 聚集是否会影响 AHSV 组装或有助于 AHSV 发病机制。在这里，我们通过针对 VP7 三聚体表面的候选氨基酸区域进行定点突变，旨在消除 VP7 的自组装。结果发现，替换七个氨基酸导致 AHSV VP7 自组装完全破坏，从而阻止了 VP7 结晶颗粒的形成，并将 VP7 转化为完全可溶的蛋白质，仍然能够与 VP3 相互作用形成类核心颗粒。这项工作进一步深入了解了 AHSV VP7 结晶颗粒的形成以及 AHSV 疫苗的成功开发。它还通过与人类病毒学中观察到的类似病毒现象进行比较，为未来的研究铺平了道路。
