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Influenza a virus polymerase is an integral component of the CPSF30-NS1A protein complex in infected cells

Rei-Lin Kuo1, Robert M Krug

  • 1Institute for Cellular and Molecular Biology, University of Texas at Austin, 78712, USA.

Journal of Virology
|December 5, 2008
PubMed

Insights

Influenza A virus NS1A protein binds cellular CPSF30, inhibiting mRNA processing. Viral polymerase proteins, particularly PA and NP, stabilize this interaction, crucial for viral replication.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • Influenza A virus NS1A protein inhibits cellular pre-mRNA 3'-end processing by binding CPSF30.
  • Specific amino acid residues (F103, M106) in NS1A are critical for CPSF30 binding stability in certain strains.

Purpose of the Study:

  • To investigate the role of viral proteins in stabilizing the NS1A-CPSF30 complex, especially in strains with differing NS1A residues.
  • To identify the specific viral components responsible for this stabilization.

Main Methods:

  • X-ray crystallography to determine the binding pocket of NS1A.
  • In vivo studies using different influenza A virus strains (Udorn/72 and Hong Kong/483/97) and their respective viral proteins.
  • Mutational analysis of NS1A protein.

Main Results:

  • The NS1A protein of H5N1 influenza (HK97) binds CPSF30 in vivo due to stabilization by cognate viral internal proteins.
  • The HK97 polymerase complex (PB1, PB2, PA, NP) stabilizes the NS1A-CPSF30 interaction.
  • Cognate PA and NP proteins are essential for stabilizing the NS1A-CPSF30 complex, while PB1 and PB2 are not required.

Conclusions:

  • The viral polymerase complex is an integral part of the NS1A-CPSF30 complex in infected cells.
  • NS1A protein primarily interacts with cognate PA and NP proteins to stabilize its binding to cellular CPSF30, impacting viral replication.

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