This result, together with the Fn/c data, indicates a delay in the infection for cells infected with the mutant viruses (while the WT-infected cells have produced enough progeny vRNPs that have been already exported to the cytoplasm at 8 h P.I., most of the cells infected with the mutant viruses have NP in their nuclei, indicating that assembly of progeny vRNPs has not been completed). Here, FN1 is linked to infection.