Figure 3. Anti VACV role of ISG15 protein expression using siRNA.

MEFs were transfected with ISG15 synthetic siRNA (siRNA1 or siRNA2), scrambled siRNA (used as a negative control) and GAPDH siRNA (used as a positive control) and 24 hours after transfection, siRNA-treated and non-treated control cells were mock- or infected with different WR or VVΔE3L viruses at 0.1 PFU/cell. A. Levels of ISG15 were measured by Western-blot using a specific murine anti-ISG15 antibody. Viral protein E3 levels were measured as a control of infection and levels of eIF2α were used as a loading control. B. CPE was visualized by phase-contrast microscopy at the indicated times p.i. C. Virus growth of WR and VVΔE3L were determined by plaque assay or by immunostaining at the indicated times p.i.