title: Identification of RNA helicase A as a cellular factor that interacts with influenza A virus NS1 protein and its role in the virus life cycle.
abstract: Influenza A virus NS1 protein has multiple functions in the infected cell during the virus life cycle. Identification of novel cellular factors that interact with NS1 and understanding their functions in virus infection are of great interest. Recombinant viruses carrying a tagged NS1 are valuable for investigation of interactions between NS1 and cellular factors in the context of virus infection. Here, we report the generation of replication-competent recombinant influenza A viruses bearing a Strep tag in the NS1 protein. Purification of a protein complex associated with Strep-tagged NS1 from virus-infected cells followed by mass spectrometry revealed a number of attractive host factors. Among them, we focused our study on RNA helicase A (RHA) in this report. Through biomedical and functional analyses, we demonstrated that RHA interacts with NS1 in an RNA-dependent manner. Knockdown of RHA resulted in a significant reduction on virus yield and polymerase activity in a minigenome assay. Our cell-free viral genome replication assay showed that viral RNA replication and transcription can be enhanced by addition of RHA, and the enhanced effect of RHA required its ATP-dependent helicase activity. In summary, we established a system to identify cellular factors that interact with NS1 protein during virus infection and furthermore demonstrated that RHA interacts with NS1 and enhances viral replication and transcription.
authors.affiliation: Vaccine and Infectious Disease Organization, University of Saskatchewan, Saskatoon, Saskatchewan, Canada.
authors.forename: Li
authors.initials: L
authors.lastname: Lin
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.forename: Hyun-Mi
authors.initials: HM
authors.lastname: Pyo
authors.forename: Xinya
authors.initials: X
authors.lastname: Lu
authors.forename: Sathya N Thulasi
authors.initials: SN
authors.lastname: Raman
authors.forename: Qiang
authors.initials: Q
authors.lastname: Liu
authors.forename: Earl G
authors.initials: EG
authors.lastname: Brown
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000818:Animals; D002460:Cell Line; D002642:Chick Embryo; D053487:DEAD-box RNA Helicases / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000235:genetics / Q000502:physiology*; D009980:Influenza A virus / Q000235:genetics / Q000502:physiology; D007251:Influenza, Human / Q000201:enzymology* / Q000235:genetics / Q000821:virology; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D017361:Viral Nonstructural Proteins / Q000235:genetics / Q000378:metabolism*; D014779:Virus Replication
chemical_list: C085820:INS1 protein, influenza virus; D009363:Neoplasm Proteins; D017361:Viral Nonstructural Proteins; C098487:DHX9 protein, human; D053487:DEAD-box RNA Helicases