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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

Nuclear export of influenza virus ribonucleoproteins: identification of an export intermediate at the nuclear

K Ma1, A M Roy, G R Whittaker

  • 1Department of Microbiology and Immunology, Cornell University, Ithaca, New York 14853, USA.

Virology
|April 6, 2001
PubMed

Insights

Influenza virus export of genomic ribonucleoproteins (vRNPs) requires the cellular factor CRM1. vRNPs accumulate at the nuclear periphery, suggesting a novel export pathway intermediate.

Area of Science:

  • Virology
  • Cell Biology
  • Molecular Biology

Background:

  • The influenza virus life cycle involves regulated transport of viral genomic ribonucleoproteins (vRNPs) from the nucleus to the cytoplasm.
  • Viral M1 and NS2 proteins have been suggested to mediate this vRNP export process.

Purpose of the Study:

  • To investigate the mechanism of influenza virus vRNP nuclear export.
  • To identify cellular factors involved in vRNP translocation across the nuclear envelope.

Main Methods:

  • Treatment of infected cells with leptomycin B (LMB), a CRM1 inhibitor.
  • Subcellular localization studies of vRNPs using microscopy.
  • In situ extraction of cells at different stages of infection.

Main Results:

  • Leptomycin B (LMB) treatment blocked vRNP nuclear export, causing accumulation at the nuclear periphery.
  • Accumulated vRNPs localized with the nuclear lamina but not with M1 or NS2 viral proteins.
  • Late in infection, vRNPs were found at the nuclear periphery, distinct from their dispersed distribution early in infection.

Conclusions:

  • The cellular factor CRM1 is essential for influenza virus vRNP nuclear export.
  • vRNPs at the nuclear periphery represent a previously unrecognized intermediate in the influenza virus nuclear export pathway.
  • This finding offers new insights into the molecular mechanisms governing influenza virus replication.

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