Fig 1: SARS-CoV-2 NP suppresses G3BP-mediated SG formation. (A) A549 cells were treated with 500 µM sodium arsenite (SA) for 1 h to induce SG assembly, and saline was used as a control. G3BP1 (green) and G3BP2 (red) were labeled to visualize SGs by immunofluorescence staining. The nuclei were stained with DAPI (blue). (B) A549 cells expressing GFP-tagged NPSARS-CoV-2 or GFP-vector were treated with 500 µM SA for 1 h to induce SG assembly. TIA1 (red) and G3BP1 (violet) were labeled to visualize SGs by immunofluorescence staining. The nuclei were stained with DAPI (blue). (C) The average SG number per cell (=10) in panel B was calculated using ImageJ software. All quantitative data are shown as the means ± SDs. **, P < 0.05. (D) A549 cells transfected with or without a G3BP1/G3BP2 plasmid were infected with SARS-CoV-2 for 24 h and treated with or without 500 µM SA during the last hour. NPSARS-CoV-2 (green) and the SG marker G3BP1 (red) were detected via immunofluorescence staining. The nuclei were stained with DAPI (blue). (E) The average SG number per cell (=10) in panel D was calculated using ImageJ software. All quantitative data are shown as the means ± SDs. **, P < 0.05.