Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China; Jiangsu Co-Innovation Center for the Prevention and Control of Important Animal Infectious Disease and Zoonose, Yangzhou University, Yangzhou 225009, PR China.
Shanghai Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Shanghai 200241, PR China.
Virus Res. 2018 Jul 15;253:87-91. doi: 10.1016/j.virusres.2018.06.006. Epub 2018 Jun 18.
Porcine galectin-3 (GAL3) is a 29-kDa protein encoded by a single gene, LGALS3, located on chromosome 1. Here, using a yeast two-hybrid screen of a cDNA library from porcine alveolar macrophage cells (PAMs), we report for the first time that GAL3 interacts with nonstructural protein 12 (Nsp12) of the porcine reproductive and respiratory syndrome virus (PRRSV). Although extensive research has focused on porcine reproductive and respiratory syndrome (PRRS), little is known about the pathogen and host interactions involving individual nonstructural viral proteins, especially Nsp12. Here, we showed that GAL3 interacted with viral Nsp12 following co-transfection of HEK293 cells with GAL3- and Nsp12-expressing plasmids. Additionally, we observed that PPRSV infection led to reduced GAL3 levels during the late phase of infection in both MARC-145 cells and PAMs. Importantly, GAL3 overexpression significantly suppressed the replication of both type 1 and 2 PRRSV strains, whereas knockout of endogenous LGALS3 in MARC-145 cells significantly increased viral titer and expression of the nucleocapsid protein. These results strongly support a direct inhibitory effect of GAL3 on PRRSV replication, which might contribute to an overall antiviral effect. Furthermore, our findings provide insights into the molecular basis of the role Nsp12 plays in PRRSV pathogenesis.
猪半乳糖凝集素-3（GAL3）是一种 29kDa 的蛋白质，由单个基因 LGALS3 编码，位于染色体 1 上。在这里，我们使用来自猪肺泡巨噬细胞（PAMs）的 cDNA 文库的酵母双杂交筛选，首次报道 GAL3 与猪繁殖与呼吸综合征病毒（PRRSV）的非结构蛋白 12（Nsp12）相互作用。尽管对猪繁殖与呼吸综合征（PRRS）进行了广泛的研究，但对于涉及单个非结构病毒蛋白的病原体和宿主相互作用知之甚少，尤其是 Nsp12。在这里，我们表明 GAL3 在共转染表达 GAL3 和 Nsp12 的质粒的 HEK293 细胞后与病毒 Nsp12 相互作用。此外，我们观察到在 MARC-145 细胞和 PAMs 中感染 PPRSV 会导致感染后期 GAL3 水平降低。重要的是，GAL3 过表达显着抑制了 1 型和 2 型 PRRSV 株的复制，而 MARC-145 细胞中内源性 LGALS3 的敲除显着增加了病毒滴度和核衣壳蛋白的表达。这些结果强烈支持 GAL3 对 PRRSV 复制的直接抑制作用，这可能有助于整体抗病毒作用。此外，我们的发现为 Nsp12 在 PRRSV 发病机制中的作用提供了分子基础的见解。
