To test whether the process of vRNP nuclear export contributes to interferon induction by NS1stop virus, we treated infected cells 3 hours post infection with the CRM1 inhibitor leptomycin B (LMB), blocking transport of influenza genomes from the nucleus, and analyzed interferon transcript expression by qPCR 8 hours post infection (Fig 5C). Here, XPO1 is linked to infection.