CGAS and infection: Furthermore, upon HSV-1 (10 MOI) infection or ISD (2 μg/ml) stimulation, the protein level and activity of cGAS were higher in mutant Omp25-5M-expressing cells than that in wild-type Omp25-expressing cells, although the protein level and activity of cGAS in both Omp25-5M-expressing cells and Omp25-expressing cells were still lower than that in Lv-GFP-infected or control cells (Figures 8E,F).