State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China
State Key Laboratory of Veterinary Etiological Biology, OIE/China National Foot-and-Mouth Disease Reference Laboratory, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou, Gansu, China.
J Virol. 2019 Mar 21;93(7). doi: 10.1128/JVI.02278-18. Print 2019 Apr 1.
The presence of sequence divergence through adaptive mutations in the major capsid protein VP1, and also in VP0 (VP4 and VP2) and VP3, of foot-and-mouth disease virus (FMDV) is relevant to a broad range of viral characteristics. To explore the potential role of isolate-specific residues in the VP0 and VP3 coding regions of PanAsia-1 strains in genetic and phenotypic properties of FMDV, a series of recombinant full-length genomic clones were constructed using Cathay topotype infectious cDNA as the original backbone. The deleterious and compensatory effects of individual amino acid substitutions at positions 4008 and 3060 and in several different domains of VP2 illustrated that the chain-based spatial interaction patterns of VP1, VP2, and VP3 (VP1-3), as well as between the internal VP4 and the three external capsid proteins of FMDV, might contribute to the assembly of eventually viable viruses. The Y2079H site-directed mutants dramatically induced a decrease in plaque size on BHK-21 cells and viral pathogenicity in suckling mice. Remarkably, the 2079H-encoding viruses displayed a moderate increase in acid sensitivity correlated with NHCl resistance compared to the Y2079-encoding viruses. Interestingly, none of all the 16 rescued viruses were able to infect heparan sulfate-expressing CHO-K1 cells. However, viral infection in BHK-21 cells was facilitated by utilizing non-integrin-dependent, heparin-sensitive receptor(s) and replacements of four uncharged amino acids at position 3174 in VP3 of FMDV had no apparent influence on heparin affinity. These results provide particular insights into the correlation of evolutionary biology with genetic diversity in adapting populations of FMDV. The sequence variation within the capsid proteins occurs frequently in the infection of susceptible tissue cultures, reflecting the high levels of genetic diversity of FMDV. A systematic study for the functional significance of isolate-specific residues in VP0 and VP3 of FMDV PanAsia-1 strains suggested that the interaction of amino acid side chains between the N terminus of VP4 and several potential domains of VP1-3 had cascading effects on the viability and developmental characteristics of progeny viruses. Y2079H in VP0 of the indicated FMDVs could affect plaque size and pathogenicity, as well as acid sensitivity correlated with NHCl resistance, whereas there was no inevitable correlation in viral plaque and acid-sensitive phenotypes. The high affinity of non-integrin-dependent FMDVs for heparin might be explained by the differences in structures of heparan sulfate proteoglycans on the surfaces of different cell lines. These results may contribute to our understanding of the distinct phenotypic properties of FMDV and .
口蹄疫病毒（FMDV）的主要衣壳蛋白 VP1 以及 VP0（VP4 和 VP2）和 VP3 中的适应性突变导致的序列差异与病毒的许多特征有关。为了探索泛亚 1 型分离株 VP0 和 VP3 编码区中分离株特异性残基在 FMDV 遗传和表型特性中的潜在作用，使用中国仓鼠毒感染 cDNA 作为原始骨架构建了一系列重组全长基因组克隆。在 VP2 的不同结构域中，位置 4008 和 3060 处单个氨基酸取代的有害和补偿效应表明，VP1、VP2 和 VP3（VP1-3）之间以及 FMDV 内部 VP4 与三个外部衣壳蛋白之间的链基空间相互作用模式可能有助于最终存活病毒的组装。Y2079H 定点突变体显著降低了 BHK-21 细胞上的蚀斑大小，并降低了乳鼠中的病毒致病性。值得注意的是，与 Y2079 编码病毒相比，编码 2079H 的病毒的酸性敏感性增加与 NHCl 抗性相关。有趣的是，所有拯救的 16 种病毒均不能感染表达硫酸乙酰肝素的 CHO-K1 细胞。然而，在 BHK-21 细胞中的病毒感染通过利用非整合素依赖性、肝素敏感的受体得到促进，并且在 FMDV 的 VP3 中的位置 3174 处替换四个不带电荷的氨基酸对肝素亲和力没有明显影响。这些结果提供了有关进化生物学与 FMDV 适应种群遗传多样性之间相关性的特定见解。在易感组织培养物的感染中，衣壳蛋白内的序列变异经常发生，反映了 FMDV 的遗传多样性水平很高。对泛亚 1 型 FMDV 中 VP0 和 VP3 分离株特异性残基的功能意义进行了系统研究，表明 VP4 的 N 末端与 VP1-3 的几个潜在结构域之间的氨基酸侧链相互作用对后代病毒的生存能力和发育特征具有级联效应。在所指示的 FMDV 中的 VP0 中的 Y2079H 可影响蚀斑大小和致病性，以及与 NHCl 抗性相关的酸性敏感性，而病毒蚀斑和酸性敏感表型之间没有必然的相关性。非整合素依赖性 FMDV 对肝素的高亲和力可以通过不同细胞系表面硫酸乙酰肝素蛋白聚糖结构的差异来解释。这些结果可能有助于我们理解 FMDV 的不同表型特性。
