Figure 7. Nuclear targeting of UL2 is important for efficient HSV-1 production. (A) Plaque analysis of WT HSV-1 (vUL2) and its derived recombinant viruses (vUL2Del, vUL2Mu and vUL2Rev) by live cells fluorescence microscope. Confluent Vero cells were infected with the indicated viruses at an MOI of 1. After adsorption at 37°C for 2 h, virus was washed away and the plate was covered with DMEM-2% FBS, then the fluorescences (GFP) derived from these viruses were analyze by fluorescence microscope after infection for 24 h. (B) Growth curve analysis of WT HSV-1 and its derived recombinant viruses. Vero cells were infected with the indicated viruses at an MOI of 1 for 6, 12, 24 and 36 h, then virus was harvested, and their titers were determined on the Vero monolayer by plaque method (with crystal violet staining). The data shown was the average results from three independent experiments. (C) Luciferase activity was used to determine the viral replication of WT HSV-1 and its derived recombinant viruses in HEK293T cells. HEK293T cells were infected with the indicated viruses at an MOI of 1 for 24 h, then luciferase activity was detected by harvesting the lysates of the virus-infected HEK293T cells. Data were expressed as means ± SD from three independent experiments. Statistical analysis was performed using student’s t test, and *** indicates P < 0.001. All scale bars indicate 30 μm.