Figure 4

Stress granule size and number are increased in GFP-FUS R495X expressing cells. (A) Clockwise order: representative single-plane phase (top left) and anti-G3BP (stress granule marker; red) immunofluorescence (top middle) confocal images of an HEK-293 cell expressing GFP-FUS WT treated with 0.5 mM sodium arsenite for 1 hr. Three-dimensional (3D) reconstruction was used to quantify stress granule volume (see Materials and methods, and C within this figure). The xy (right) and yz (bottom; view along arrow in xy image) planes for this 3D reconstructed image are shown; the stress granule highlighted in yellow is marked for volume analysis. Scale bar = 10 μm. (B) Representative maximum projection confocal images of GFP-FUS WT and GFP-FUS R495X expressing cells treated as in (A) exemplify the size and number of stress granules for each line. Scale bar = 10 μm. (C and D) GFP-FUS R495X expressing cells contain stress granules with larger volume (C) and in greater abundance (D) relative to cells expressing GFP-FUS WT. Asterisks indicate statistically significant differences between cell lines as determined by the Student’s t-test (**P < 0.01, *P < 0.05) on data from n=3 independent experiments. All error bars represent SEMs.