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Co-immunoprecipitation of the Mouse Mx1 Protein with the Influenza A Virus Nucleoprotein
Published on: April 21, 2015
Interferon-inducible Mx gene expression in cotton rats: cloning, characterization, and expression during influenza
Lioubov M Pletneva1, Otto Haller, David D Porter
1Virion Systems, Inc., Rockville, MD 20850, USA.
Abstract:
Mx proteins belong to the superfamily of large GTPases with antiviral activity against a wide range of RNA viruses. In vivo, the expression of Mx genes is tightly regulated by the presence of type I interferons (IFNs), and their induction has been described during several viral infections. However, because of the absence of functional Mx genes in most common laboratory strains of mice, in vivo studies of the expression of these genes during viral infection have been hampered. We have cloned the cDNAs for the cotton rat homologs of Mx1 and Mx2 genes that encode full-length proteins. Mx1 localized in the nucleus, whereas Mx2, as its human homolog MxA, localized in the cytoplasm. The expression of Mx genes in cotton rat cells was induced by type I IFNs (IFN-alpha and IFN-beta) but induced only marginally with type II IFN (IFN-gamma). In vivo, the expression of Mx genes was dramatically augmented in lungs of cotton rats infected with influenza virus. The expression of Mx genes and protein(s) was dependent on the dose of virus and the time postinfection for the analysis. Our data present for the first time a complete analysis of the kinetics of expression of these influenza resistant genes in vivo and underscore the fidelity and sensitivity of the cotton rat model for the study of influenza viral infection.
Insights
Cotton rats possess functional Mx genes, crucial for antiviral defense against RNA viruses like influenza. Their expression is induced by interferons and significantly increases during influenza infection, making cotton rats a valuable model for studying viral resistance.
Area of Science:
- Virology
- Immunology
- Molecular Biology
Background:
- Mx proteins are large GTPases with broad antiviral activity against RNA viruses.
- Mx gene expression is interferon-regulated and induced during viral infections.
- Limited availability of functional Mx genes in common lab mice hinders in vivo studies.
Purpose of the Study:
- To clone and characterize cotton rat Mx1 and Mx2 genes.
- To investigate the regulation and in vivo expression kinetics of Mx genes during influenza virus infection.
Main Methods:
- Cloning of cotton rat Mx1 and Mx2 cDNAs.
- Subcellular localization studies of Mx1 and Mx2 proteins.
- Induction of Mx gene expression by type I and type II interferons in cotton rat cells.
- Analysis of Mx gene and protein expression in cotton rat lungs following influenza virus infection.
Main Results:
- Mx1 protein localized to the nucleus; Mx2 to the cytoplasm.
- Type I interferons (IFN-alpha, IFN-beta) strongly induced Mx gene expression; Type II IFN (IFN-gamma) had minimal effect.
- Influenza virus infection dramatically upregulated Mx gene and protein expression in cotton rat lungs.
- Expression levels were dependent on viral dose and time post-infection.
Conclusions:
- The cotton rat is a suitable model for studying Mx gene function and influenza virus infection in vivo.
- Mx gene expression kinetics during influenza infection are fully characterized in this model.
- This study provides a comprehensive analysis of Mx gene induction during viral challenge.
