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Translation without eIF2 promoted by poliovirus 2A protease

Natalia Redondo1, Miguel Angel Sanz, Ewelina Welnowska

  • 1Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Universidad Autónoma de Madrid, Madrid, Spain. nsevillano@cbm.uam.es

Plos One
|October 18, 2011
PubMed

Insights

Poliovirus translation uses a dual mechanism for protein synthesis initiation. The viral protease 2A(pro) enables eIF2-independent translation, crucial for late-stage infection.

Area of Science:

  • Molecular Biology
  • Virology
  • Biochemistry

Background:

  • Picornaviruses, including poliovirus, are RNA viruses that infect host cells.
  • Translation initiation in eukaryotes typically requires the eukaryotic initiation factor 2 (eIF2).
  • Picornavirus RNA translation is known to utilize internal ribosome entry site (IRES) elements.

Purpose of the Study:

  • To investigate the mechanism of poliovirus translation initiation during infection.
  • To determine the role of eIF2 and viral proteins in poliovirus RNA translation.
  • To elucidate the dual mechanism of translation initiation employed by poliovirus.

Main Methods:

  • Cell-free translation systems.
  • Analysis of poliovirus non-structural proteins, specifically 2A(pro).
  • Infection of culture cells and assessment of protein synthesis.

Main Results:

  • Poliovirus translation occurs at late infection times when eIF2 is phosphorylated and inactivated.
  • The viral protease 2A(pro) is sufficient to confer eIF2 independence for IRES-driven translation.
  • High levels of 2A(pro) are necessary for eIF2 independence, and this function requires 2A(pro)'s ability to cleave eIF4G.

Conclusions:

  • Poliovirus employs a dual mechanism for translation initiation, adapting to host cell conditions.
  • Viral protease 2A(pro) plays a key role in overcoming eIF2 inactivation, enabling viral protein synthesis.
  • This discovery opens new research avenues in picornavirus protein synthesis and host-pathogen interactions.

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