Based on the epistasis analysis, the transcriptional activity of the IFNB1 promoter is slightly affected by ectopic expression of constitutively active IRF3(5D) [22], while it was completely blocked in SeV infected or MAVS overexpressing cells transduced at a high multiplicity of infection (MOI of 20) with lentiviral-expressing shRNA (Fig 1E). This evidence concerns the gene IRF3 and infection.