MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
MOE Joint International Research Laboratory of Animal Health and Food Safety, College of Veterinary Medicine, Nanjing Agricultural University, Nanjing 210095, China.
Vet Microbiol. 2022 Nov;274:109555. doi: 10.1016/j.vetmic.2022.109555. Epub 2022 Sep 6.
Japanese encephalitis virus (JEV) is a major causative agent of neurological infection affecting humans and pigs. Human T Cell Immunoglobulin and Mucin Domain 1 (hTIM-1) enhances the infection of JEV through virion-associated phosphatidylserine (PS) binding. Here, five swine TIM-1 (sTIM-1) gene variants were cloned from pig lung tissues by reverse-transcriptase polymerase chain reaction (RT-PCR). Sequence alignment analysis revealed that the gene homology between the sTIM-1 and hTIM-1 was 42.3-43.8%. Furthermore, ectopic expression of all five sTIM-1 variants in 293 T cells can promote JEV entry and infection. However, sTIM-1 V3 exhibited significantly less potent at promoting virus entry compared to the other four variants. Further studies revealed that the 34th amino acid of sTIM-1is critical for the entry of JEV, which is Pro34 in sTIM-1V3 while Leu34 in other four sTIM-1 variants. Mechanically, leucine at locus 34 was associated with the membrane distribution of sTIM-1, thereby affecting viral entry and infection. In total, our findings provide evidence that the PS receptor sTIM-1 promotes the infection of JEV and that the 34th amino acid position is critical for sTIM-1 to mediate viral infection.
日本脑炎病毒 (JEV) 是一种主要的神经感染病原体，可感染人类和猪。人 T 细胞免疫球蛋白和粘蛋白结构域 1（hTIM-1）通过与病毒相关的磷脂酰丝氨酸（PS）结合增强 JEV 的感染。在这里，通过逆转录聚合酶链反应 (RT-PCR) 从猪肺组织中克隆了五个猪 TIM-1（sTIM-1）基因变体。序列比对分析表明，sTIM-1 和 hTIM-1 之间的基因同源性为 42.3-43.8%。此外，所有五个 sTIM-1 变体在 293T 细胞中的异位表达均可促进 JEV 的进入和感染。然而，sTIM-1 V3 促进病毒进入的能力明显低于其他四个变体。进一步的研究表明，sTIM-1 的第 34 个氨基酸对于 JEV 的进入至关重要，sTIM-1 V3 中的第 34 位氨基酸为脯氨酸（Pro34），而其他四个 sTIM-1 变体中的第 34 位氨基酸为亮氨酸（Leu34）。从机制上讲，第 34 位的亮氨酸与 sTIM-1 的膜分布有关，从而影响病毒的进入和感染。总之，我们的研究结果表明 PS 受体 sTIM-1 促进了 JEV 的感染，并且第 34 个氨基酸位置对于 sTIM-1 介导病毒感染至关重要。
