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The pp24 phosphoprotein of Mason-Pfizer monkey virus contributes to viral genome packaging

Christopher R Bohl1, Shanna M Brown, Robert A Weldon

  • 1School of Biological Sciences, The Nebraska Center for Virology, University of Nebraska, Lincoln, 68588, USA. cbohl1@hotmail.com

Retrovirology
|November 9, 2005
PubMed
Abstract

Insights

A conserved KKPKR motif in the Np24 protein of Mason-Pfizer monkey virus is essential for viral RNA packaging and replication. This motif is crucial for Gag

Area of Science:

  • Virology
  • Molecular Biology
  • Retroviral Research

Background:

  • The Gag protein of Mason-Pfizer monkey virus (MPMV) is processed into Np24 and pp16/18 during maturation.
  • pp16/18 has a late domain for budding, while Np24's function remained unknown despite its role in replication.

Purpose of the Study:

  • To elucidate the function of the Np24 protein domain in the MPMV life cycle.
  • To identify the specific region within Np24 responsible for its role in viral replication.

Main Methods:

  • Sequence analysis to identify conserved motifs within Np24.
  • Mutagenesis studies to assess the role of the KKPKR motif in viral replication, assembly, budding, and packaging.
  • Analysis of Gag protein association with nuclear pores.

Main Results:

  • A highly conserved KKPKR motif was identified in the Np24 domain across betaretroviruses.
  • This KKPKR motif is critical for viral replication but not for procapsid assembly, membrane targeting, budding, release, maturation, or glycoprotein packaging.
  • Deletion of the KKPKR motif significantly reduced viral RNA packaging (6-8 fold) and altered Gag's association with nuclear pores.

Conclusions:

  • The Np24 domain, specifically the KKPKR motif, is vital for efficient viral RNA packaging.
  • These findings support the importance of Gag's intracellular targeting to nuclear compartments for successful retroviral replication.

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