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Nucleus-targeting domain of the matrix protein (M1) of influenza virus

Z Ye1, D Robinson, R R Wagner

  • 1Department of Microbiology, University of Virginia School of Medicine, Charlottesville 22908.

Journal of Virology
|March 1, 1995
PubMed

Insights

The influenza virus M1 protein

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Influenza virus matrix protein M1 plays a crucial role in viral assembly and uncoating.
  • Understanding the intracellular transport mechanisms of viral proteins is essential for comprehending the viral life cycle.

Purpose of the Study:

  • To identify the specific region within the influenza virus M1 protein responsible for its nuclear localization.
  • To investigate the role of a putative nuclear localization signal (NLS) in M1 protein transport.

Main Methods:

  • Immunofluorescent staining to visualize M1 protein localization in transfected cells.
  • Site-directed mutagenesis to create M1 protein variants with deletions or substitutions.
  • Transfection of CV1 cells with recombinant vectors expressing wild-type and mutant M1 proteins.
  • Nuclear import assays using isolated cell nuclei and synthetic M1 protein peptides.

Main Results:

  • The M1 protein is transported into the nucleus of transfected cells independently of other viral proteins.
  • A specific amino acid sequence, RKLKR at positions 101-105, was identified as essential for M1 nuclear import.
  • Truncated M1 proteins retaining the RKLKR sequence were nuclear-localized, while those lacking it remained cytoplasmic.
  • Synthetic peptides containing the RKLKR sequence were imported into isolated nuclei, confirming its function as an NLS.

Conclusions:

  • The amino acid sequence 101RKLKR105 functions as the nuclear localization signal for the influenza virus M1 protein.
  • This finding elucidates a key mechanism governing the intracellular trafficking of a critical influenza virus component.
  • The identified NLS provides a target for further research into influenza virus replication and potential antiviral strategies.

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