Resumen
Mice are not natural hosts for influenza A viruses (IAVs), but they are useful models for studying antiviral immune responses and pathogenesis. Serial passage of IAV in mice invariably causes the emergence of adaptive mutations and increased virulence. Here, we report the adaptation of IAV reference strain A/California/07/2009(H1N1) (also known as CA/07) in outbred Swiss Webster mice. Serial passage led to increased virulence and lung titers, and dissemination of the virus to brains. We adapted a deep-sequencing protocol to identify and enumerate adaptive mutations across all genome segments. Among mutations that emerged during mouse-adaptation, we focused on amino acid substitutions in polymerase subunits: polymerase basic-1 (PB1) T156A and F740L and polymerase acidic (PA) E349G. These mutations were evaluated singly and in combination in minigenome replicon assays, which revealed that PA E349G increased polymerase activity. By selectively engineering three PB1 and PA mutations into the parental CA/07 strain, we demonstrated that these mutations in polymerase subunits decreased the production of defective viral genome segments with internal deletions and dramatically increased the release of infectious virions from mouse cells. Together, these findings increase our understanding of the contribution of polymerase subunits to successful host adaptation.
| Idioma original | English |
|---|---|
| Número de artículo | 272 |
| Publicación | Viruses |
| Volumen | 10 |
| N.º | 5 |
| DOI | |
| Estado | Published - may. 18 2018 |
Nota bibliográfica
Funding Information:This work was supported by CIHR Operating Grants MOP-136817 and PJT 148727,NSERC Discovery Grant RGPIN/341940-2012, and operating funds from Public Health Agency of Canada/CIHR Influenza Research Network. Acknowledgments: We thank members of the McCormick lab for critical reading of the manuscript. We thank Yoshihiro Kawaoka (University of Wisconsin-Madison, Madison, WI, USA), Richard Webby (St. Jude Children’s Hospital, Memphis, TN, USA) and Georg Kochs (University of Freiburg, Freiburg, Germany) for reagents. We thank members of the Integrated Microbiome Resource (IMR) for deep sequencing and bioinformatics support, with a special thank you to Gavin Douglas. We thank Stephen Whitefield at the Dalhousie University Faculty of Medicine Cellular & Molecular Digital Imaging Core Facility for microscopy support. We thank the members of the Dalhousie Animal Care Facility for their support. This work was supported by CIHR Operating Grants MOP-136817 and PJT 148727.
Funding Information:
Acknowledgments: We thank members of the McCormick lab for critical reading of the manuscript. We thank Yoshihiro Kawaoka (University of Wisconsin-Madison, Madison, WI, USA), Richard Webby (St. Jude Children’s Hospital, Memphis, TN, USA) and Georg Kochs (University of Freiburg, Freiburg, Germany) for reagents. We thank members of the Integrated Microbiome Resource (IMR) for deep sequencing and bioinformatics support, with a special thank you to Gavin Douglas. We thank Stephen Whitefield at the Dalhousie University Faculty of Medicine Cellular & Molecular Digital Imaging Core Facility for microscopy support. We thank the members of the Dalhousie Animal Care Facility for their support. This work was supported by CIHR Operating Grants MOP-136817 and PJT 148727.
Funding Information:
Funding: This work was supported by CIHR Operating Grants MOP-136817 and PJT 148727, NSERC Discovery Grant RGPIN/341940-2012, and operating funds from Public Health Agency of Canada/CIHR Influenza Research Network.
Publisher Copyright:
© 2018 by the authors. Licensee MDPI, Basel, Switzerland.
ASJC Scopus Subject Areas
- Infectious Diseases
- Virology
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