title: Myxovirus resistance gene A (MxA) expression suppresses influenza A virus replication in alpha interferon-treated primate cells.
abstract: Alpha interferon (IFN-α) production is triggered when influenza virus RNA is detected by appropriate pattern recognition receptors in the host cell. IFN-α induces the expression of more than 300 interferon-stimulated genes (ISGs), and this blunts influenza virus replication. The human ISG MxA can inhibit influenza A virus replication in mouse cells by interfering with a step in the virus replication cycle after primary transcription of the negative-strand RNA genome to mRNA (J. Pavlovic, O. Haller, and P. Staeheli, J. Virol. 66:2564-2569, 1992). To determine the role of MxA in blocking human influenza A virus replication in primate cells, we manipulated MxA expression in rhesus kidney epithelial cells (LLC-MK(2)) and human lung carcinoma cells (A549). We found that IFN-α treatment prior to influenza virus infection suppressed virus replication and induced the expression of many ISGs, including MxA. However, IFN-α-mediated suppression of virus replication was abolished by small interfering RNA (siRNA) knockdown of MxA expression in IFN-treated cells. In addition, influenza virus replication was suppressed in Vero cells stably transfected with MxA. A strand-specific reverse transcription-PCR (RT-PCR) assay showed that positive-strand influenza virus mRNA and negative-strand genomic RNA (gRNA) accumulated to high levels at 8 h after infection in control Vero cells containing the empty vector. However, in Vero cells stably transfected with MxA positive-strand influenza virus mRNA, complementary positive-strand influenza virus genome RNA (cRNA) and influenza virus gRNA were drastically suppressed. Thus, in primate cells, MxA inhibits human seasonal influenza virus replication at a step prior to primary transcription of gRNA into mRNA. Taken together, these results demonstrate that MxA mediates control of influenza virus replication in primate cells treated with IFN-α.
authors.affiliation: Center for Comparative Medicine, University of California, Davis, Davis, CA, USA.
authors.forename: Shannon R
authors.initials: SR
authors.lastname: Matzinger
authors.forename: Timothy D
authors.initials: TD
authors.lastname: Carroll
authors.forename: Joseph C
authors.initials: JC
authors.lastname: Dutra
authors.forename: Zhong-Min
authors.initials: ZM
authors.lastname: Ma
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Miller
mesh_terms: D000818:Animals; D002460:Cell Line; D002522:Chlorocebus aethiops; D019204:GTP-Binding Proteins / Q000096:biosynthesis* / Q000276:immunology*; D006801:Humans; D009980:Influenza A virus / Q000276:immunology* / Q000502:physiology*; D016898:Interferon-alpha / Q000276:immunology*; D008253:Macaca mulatta; D064547:Myxovirus Resistance Proteins; D012367:RNA, Viral / Q000378:metabolism; D014158:Transcription, Genetic; D014779:Virus Replication
chemical_list: D016898:Interferon-alpha; C579071:MX1 protein, human; D064547:Myxovirus Resistance Proteins; D012367:RNA, Viral; D019204:GTP-Binding Proteins