Fig 4.

IRF-3 mediates IFN-β transcriptional induction and enhances neuronal survival in primary mouse cortical neurons. (A) Primary cortical neurons derived from wild-type (wt) C57BL/6 (lanes 1 to 6) and IRF-3^−/− (lanes 7 to 12) mice were either mock infected (lanes 1 to 3 and 7 to 9) or infected with WEEV at an MOI of 1 (lanes 4 to 6 and 10 to 12), and IFN-β, WEEV E1, and rRNA transcript levels were assayed by semiquantitative RT-PCR at 20 hpi. Adjacent lanes for individual samples represent results using 10-fold dilutions of cDNA. (B and C) Primary cortical neurons derived from wt C57BL/6 or IRF-3^−/− mice were infected with WEEV at the indicated MOI, and the percentages of viability relative to mock-infected controls (B) and infectious viral titers in supernatants (C) were measured at 48 hpi. Viral titers also were measured at 8 and 20 hpi and showed no difference between wt and IRF-3^−/− neurons for an MOI of either 1 or 0.01 (data not shown). *, P < 0.05.