FIGURE 4.

IRF-3 phosphorylation following infection of PKR⁺, PKR^kd, and PKR^kd-con with mutant viruses expressing truncated E3L proteins lacking the ZBM or RBM domain. Whole cell extracts were prepared from uninfected cells (Mock) or infected cells at 10 h post-infection with either WT or the following E3L deletion mutant viruses: ΔE3L deletion mutant; Δ26C mutant lacking RBM; Δ83N mutant lacking ZBM. Cells used were as follows: PKR-sufficient parental (PKR⁺) and knockdown control (PKR^kd-con); PKR-deficient knockdown (PKR^kd). Western immunoblot analysis was carried out with antibody against IRF-3, PKR, and β-actin as a loading control.