FIG. 1.

Cells inducibly expressing PKR are sensitive to WSN-induced apoptosis. Murine 3T3 L1 cells (VEC, control cells carrying vector alone; PKR-WT, cells overexpressing PKR under control of a tetracycline/doxycycline-inducible promoter; PKR-Δ6, cells overexpressing a dominant-negative variant of PKR under the same inducible promoter) were infected with WSN at an MOI of 10. (Top) Cells mock infected or infected with WSN were photographed 24 h postinfection (magnification, ×100). (Bottom) WSN-infected cells were fixed and incubated with the TUNEL reaction mixture (see Materials and Methods) to detect apoptotic cells and subsequently stained with propidium iodide to detect all cells (magnification, ×100).