The Influenza B Virus Nonstructural NS1 Protein Is Essential for Efficient Viral Growth and Antagonizes Beta Interferon Induction
AUTOR(ES)
Dauber, Bianca
FONTE
American Society for Microbiology
RESUMO
We analyzed the functions of the influenza B virus nonstructural NS1-B protein, both by utilizing a constructed mutant virus (ΔNS1-B) lacking the NS1 gene and by testing the activities of the protein when expressed in cells. The mutant virus replicated to intermediate levels in 6-day-old embryonated chicken eggs that contain an immature interferon (IFN) system, whereas older eggs did not support viral propagation to a significant extent. The ΔNS1-B virus was a substantially stronger inducer of beta IFN (IFN-β) transcripts in human lung epithelial cells than the wild type, and furthermore, transiently expressed NS1-B protein efficiently inhibited virus-dependent activation of the IFN-β promoter. Interestingly, replication of the ΔNS1-B knockout virus was attenuated by more than 4 orders of magnitude in tissue culture cells containing or lacking functional IFN-α/β genes. These findings show that the NS1-B protein functions as a viral IFN antagonist and indicate a further requirement of this protein for efficient viral replication that is unrelated to blocking IFN effects.
ACESSO AO ARTIGO
http://www.pubmedcentral.nih.gov/articlerender.fcgi?artid=369500Documentos Relacionados
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