Fig. 4.

cGAS is colocalized with cytoplasmic chromatin in syncytial cells. a Representative confocal immunofluorescence images of co-cultured cells stained for DNA and cGAS-HA. HEK293T cells transfected with plasmids expressing spike (HEK293T(S)) were co-cultured with cGAS-null HeLa-ACE2 cells transfected with cGAS-HA. After 8 h, cells were stained with DAPI (blue) and anti-HA (red) antibody as indicated. Triangles indicate colocalization of cGAS with cytosolic chromatin. b Representative confocal immunofluorescence images of co-cultured cells stained for DNA, cGAS-HA, and Lamin B1. Co-culture experiments were performed as described in a. Cells were stained with DAPI (blue), anti-HA (red), and anti-Lamin B1 (green) antibodies. Three-dimensional reconstructed images based on z-stack images were displayed as volume view. c, d Extracted frames from live-cell imaging of co-cultured cells using confocal microscopy. HEK293T(S) cells transfected with plasmids expressing cGAS-GFP were co-cultured with cGAS-null HeLa-ACE2 cells transfected with plasmids expressing cGAS-GFP. After 1 h, cells were stained with DRAQ5 (purple) for visualizing DNA and subjected to live-cell imaging. e Co-culture experiments were performed as described in a. Cells were stained with DAPI (blue), anti-HA (red) antibody, and anti-γH2AX (green) antibody. Scale bars, 20 μm or 5 μm (inset)