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Translation of viral mRNA without active eIF2: the case of picornaviruses

Ewelina Welnowska1, Miguel Angel Sanz, Natalia Redondo

  • 1Centro de Biología Molecular Severo Ochoa (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain.

Plos One
|July 23, 2011
PubMed

Insights

Encephalomyocarditis virus protein synthesis late in infection does not require eukaryotic initiation factor 2 alpha (eIF2α). This suggests picornavirus RNA translation uses a dual mechanism, switching to eIF2α independence after viral RNA replication.

Area of Science:

  • Virology
  • Molecular Biology
  • Biochemistry

Background:

  • Picornavirus RNA translation typically requires active eukaryotic initiation factor 2 alpha (eIF2α).
  • Previous studies established eIF2α's role in cell-free systems and transfected cells.

Purpose of the Study:

  • To investigate the role of eIF2α in encephalomyocarditis virus (EMCV) protein synthesis during different infection stages.
  • To determine if other picornaviruses also exhibit altered eIF2α dependence during late infection.

Main Methods:

  • Utilized arsenite to induce eIF2α phosphorylation and inhibit translation.
  • Employed eIF2α depletion in HeLa cells.
  • Performed immunofluorescence analysis to assess colocalization of eIF2α with viral components.

Main Results:

  • EMCV protein synthesis late in infection was resistant to eIF2α phosphorylation inhibitors.
  • Early EMCV translation was blocked by eIF2α inactivation; late translation was unaffected by eIF2α depletion.
  • eIF2α did not colocalize with ribosomes or EMCV 3D polymerase during late infection.

Conclusions:

  • eIF2α is not involved in EMCV RNA translation during late infection stages.
  • Other picornaviruses (foot-and-mouth disease virus, mengovirus, poliovirus) also show eIF2α independence during maximal translation.
  • Picornavirus RNA translation likely employs a dual mechanism, requiring eIF2α for initial RNA translation but switching to eIF2α independence post-replication.

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