Tyrosines in the Influenza A Virus M2 Protein Cytoplasmic Tail Are Critical for Production of Infectious Virus Particles

W Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins University, Bloomberg School of Public Health, 615 North Wolfe Street, Suite 5132, Baltimore, Maryland 21205, USA.
Journal of Virology (Impact Factor: 4.44). 09/2010; 84(17):8765-76. DOI: 10.1128/JVI.00853-10
Source: PubMed


The cytoplasmic tail of the influenza A virus M2 protein is required for the production of infectious virions. In this study,
critical residues in the M2 cytoplasmic tail were identified by single-alanine scanning mutagenesis. The tyrosine residue
at position 76, which is conserved in >99% of influenza virus strains sequenced to date, was identified as being critical
for the formation of infectious virus particles using both reverse genetics and a protein trans-complementation assay. Recombinant viruses encoding M2 with the Y76A mutation demonstrated replication defects in MDCK cells
as well as in primary differentiated airway epithelial cell cultures, defects in the formation of filamentous virus particles,
and reduced packaging of nucleoprotein into virus particles. These defects could all be overcome by a mutation of serine to
tyrosine at position 71 of the M2 cytoplasmic tail, which emerged after blind passage of viruses containing the Y76A mutation.
These data confirm and extend our understanding of the significance of the M2 protein for infectious virus particle assembly.

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    • "M2e5× VLPs that contain a tandem repeat of M2e sequences derived from human (2×), swine (1×) and avian (2×) influenza viruses were produced as previously described [11]. The M2 expressing MDCK cell line was kindly provided by Dr. Andrew Pekosz [15] "
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    • "The M2 cytoplasmic tail was also shown to be important for the efficient production of infectious viral particles , as mutations between residues 70 – 77 impaired vRNP incorporation into budding virions ( Grantham et al . , 2010 ; McCown and Pekosz , 2005 ; McCown and Pekosz , 2006 ) . However , it is not known if the cytoplasmic tail of M2 binds NP directly or if alterations in the M2 - M1 interaction are responsible for the reduction in vRNP packaging . Additional evidence for the interaction between M2 and M1 comes from the observation that treatment of influ"
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