Joint International Research Laboratory of Animal Health and Food Safety & Single Molecule Nanometry Laboratory (Sinmolab), Nanjing Agricultural University, Nanjing, China.
Computational Optics Laboratory, School of Science, Jiangnan University, Wuxi, China.
FASEB J. 2020 Mar;34(3):4653-4669. doi: 10.1096/fj.201902455R. Epub 2020 Feb 4.
Transmissible gastroenteritis virus (TGEV) is a swine enteropathogenic coronavirus that causes significant economic losses in swine industry. Current studies on TGEV internalization mainly focus on viral receptors, but the internalization mechanism is still unclear. In this study, we used single-virus tracking to obtain the detailed insights into the dynamic events of the TGEV internalization and depict the whole sequential process. We observed that TGEVs could be internalized through clathrin- and caveolae-mediated endocytosis, and the internalization of TGEVs was almost completed within ~2 minutes after TGEVs attached to the cell membrane. Furthermore, the interactions of TGEVs with actin and dynamin 2 in real time during the TGEV internalization were visualized. To our knowledge, this is the first report that single-virus tracking technique is used to visualize the entire dynamic process of the TGEV internalization: before the TGEV internalization, with the assistance of actin, clathrin, and caveolin 1 would gather around the virus to form the vesicle containing the TGEV, and after ~60 seconds, dynamin 2 would be recruited to promote membrane fission. These results demonstrate that TGEVs enter ST cells via clathrin- and caveolae-mediated endocytic, actin-dependent, and dynamin 2-dependent pathways.
传染性胃肠炎病毒（TGEV）是一种猪肠道致病性冠状病毒，它会给养猪业造成巨大的经济损失。目前关于 TGEV 内化的研究主要集中在病毒受体上，但内化机制仍不清楚。在本研究中，我们使用单病毒跟踪技术来深入了解 TGEV 内化的动态事件，并描绘出整个连续过程。我们观察到，TGEV 可以通过网格蛋白和小窝蛋白介导的内吞作用内化，并且 TGEV 在附着到细胞膜后几乎在 2 分钟内完成内化。此外，还实时观察到 TGEV 内化过程中与肌动蛋白和动力蛋白 2 的相互作用。据我们所知，这是首次使用单病毒跟踪技术来可视化 TGEV 内化的整个动态过程的报告：在 TGEV 内化之前，在肌动蛋白、网格蛋白和小窝蛋白 1 的协助下，网格蛋白、小窝蛋白 1 会聚集在病毒周围形成含有 TGEV 的囊泡，大约 60 秒后，动力蛋白 2 会被招募来促进膜裂变。这些结果表明，TGEV 通过网格蛋白和小窝蛋白介导的内吞作用、肌动蛋白依赖性和动力蛋白 2 依赖性途径进入 ST 细胞。
