FIG. 6.

The VP1-2 NLS is required for complementation of HSV-1ΔUL36 virus. (a) COS cells were transfected in triplicate with 1 μg of the pEGFP, pcDNA3-SV5-UL36fl, or pcDNA3-SV5-UL36ΔNLS vector. After 24 h posttransfection, the cells were infected with HSV-1 KΔUL36 at 5 PFU/cell and unabsorbed virus was inactivated by an acid wash (40 mM citric acid, 135 mM NaCl, 10 mM KCl, pH 3.0). At 16 h after infection, cells and media were harvested together, lysed by freeze/thawing three times, and the viral yield determined by plaque assay on HS30 cells. Results are plotted as virus yield in PFU/ml with the average and standard deviation for each series. (b) In parallel, cells were examined for expression levels by Western blotting of both proteins, VP1-2 and VP1-2ΔNLS, as described in Materials and Methods. Actin levels were determined as well as a loading control.