IMPA1 and infection: By 8 hpi, the nuclei of MEFwt (Fig 4Ai), MEF-Impα1-/- (Fig 4Ci), MEF-Impα3-/- (Fig 4Di), and MEF-Impα4-/- (Fig 4Ei) contained prominent amounts of nuclear capsid proteins but no nuclear capsid proteins were detected upon infection in the presence of nocodazole (Fig 4Bi).