Assessment of Ifnb1/Ifnβ1 mRNA production following infection of WT and ΔWD MEFs with IAV showed similar induction of Ifnb1/Ifnβ1 mRNA in both cell types during the first 90 minutes, but there was a dramatic 5-fold increase in Ifnb1/Ifnβ1 transcription at 120 min in ΔWD MEFs compared to controls (Figure 2E). Here, IFNB1 is linked to infection.