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Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes
09:35

Purification and Visualization of Influenza A Viral Ribonucleoprotein Complexes

Published on: February 9, 2009

Polyuridylated mRNA synthesized by a recombinant influenza virus is defective in nuclear export

L L Poon1, E Fodor, G G Brownlee

  • 1Sir William Dunn School of Pathology, University of Oxford, Oxford, United Kingdom.

Journal of Virology
|December 10, 1999
PubMed

Insights

The influenza virus poly(A) tail is crucial for mRNA nuclear export. Mutating the poly(A) signal in neuraminidase mRNA results in nuclear retention and an attenuated virus, suggesting potential for live attenuated vaccines.

Area of Science:

  • Virology
  • Molecular Biology
  • Vaccine Development

Background:

  • Influenza virus mRNA polyadenylation is critical for viral replication.
  • The poly(A) tail is synthesized by copying a U-rich sequence on the viral RNA template.
  • Nuclear export of viral mRNA is essential for protein synthesis and viral propagation.

Purpose of the Study:

  • To investigate the role of the poly(A) tail in influenza virus mRNA nuclear export.
  • To engineer a novel influenza virus with a mutated poly(A) signal in its neuraminidase gene.
  • To assess the impact of altered polyadenylation on viral replication and phenotype.

Main Methods:

  • Site-directed mutagenesis of the neuraminidase vRNA U-track to an A-track.
  • Generation of a recombinant influenza A/WSN/33 virus carrying the mutated NA vRNA.
  • Analysis of NA mRNA localization (nuclear vs. cytoplasmic) in infected cells.
  • Quantification of neuraminidase protein expression and assessment of viral attenuation.

Main Results:

  • The engineered virus synthesized poly(U)-tailed NA mRNA instead of poly(A)-tailed NA mRNA.
  • Poly(U)-tailed NA mRNA was predominantly retained in the nucleus.
  • Polyadenylated NA mRNA was efficiently transported to the cytoplasm.
  • The mutant virus exhibited reduced neuraminidase production and an attenuated phenotype.

Conclusions:

  • The poly(A) tail is essential for the efficient nuclear export of influenza virus NA mRNA.
  • Mutations in the poly(A) signal can lead to mRNA nuclear retention and viral attenuation.
  • This poly(A) signal mutant influenza virus may serve as a live attenuated vaccine candidate.
  • The mutant virus provides a valuable model for studying mRNA nuclear export mechanisms.

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