PA-X is an avian virulence factor in H9N2 avian influenza virus. (5th March 2021)

• Record Type: Journal Article
• Authors: Clements, Anabel L.; Peacock, Thomas P.; Sealy, Joshua E.; Lee, Hui Min; Hussain, Saira; Sadeyen, Jean-Remy; Shelton, Holly; Digard, Paul; Iqbal, Munir
• Is Part Of: Journal of general virology. Volume 102:Number 3(2021)
• Publication Date: 2021-03-05
• Subjects: accessory protein -- avian influenza -- Influenza -- PA-X -- poultry -- virulence factor; Virology -- Periodicals; Viruses; Microbiology; Virology; Virologie -- Périodiques; Microbiologie -- Périodiques; Virology; Virologie; Virologie; Electronic journals; Periodical; Periodicals; 579.2
• DOI: 10.1099/jgv.0.001531
• Languages: English
• ISSNs: 0022-1317

Abstract

Abstract : Influenza A viruses encode several accessory proteins that have host- and strain-specific effects on virulence and replication. The accessory protein PA-X is expressed due to a ribosomal frameshift during translation of the PA gene. Depending on the particular combination of virus strain and host species, PA-X has been described as either acting to reduce or increase virulence and/or virus replication. In this study, we set out to investigate the role PA-X plays in H9N2 avian influenza viruses, focusing on the natural avian host, chickens. We found that the G1 lineage A/chicken/Pakistan/UDL-01/2008 (H9N2) PA-X induced robust host shutoff in both mammalian and avian cells and increased virus replication in mammalian, but not avian cells. We further showed that PA-X affected embryonic lethality in ovo and led to more rapid viral shedding and widespread organ dissemination in vivo in chickens. Overall, we conclude PA-X may act as a virulence factor for H9N2 viruses in chickens, allowing faster replication and wider organ tropism.