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Localization of self-interacting domains within betaretrovirus Gag polyproteins

Ales Zábranský1, Michael Sakalian, Iva Pichová

  • 1Department of Protein Biochemistry, Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo n.2, Prague 6, 16610, Czech Republic. ales@uochb.cas.cz

Virology
|February 1, 2005
PubMed

Insights

Betaretroviruses like M-PMV and MMTV assemble capsids via Gag protein interactions. Mason-Pfizer monkey virus relies on its p12 domain, while mouse mammary tumor virus uses multiple domains for this crucial step.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • Betaretroviruses exhibit cytoplasmic capsid preassembly.
  • Mason-Pfizer monkey virus (M-PMV) Gag protein utilizes an Internal Scaffold Domain (ISD) in the p12 region for this process.
  • Understanding Gag-Gag interactions is key to viral assembly mechanisms.

Purpose of the Study:

  • To further characterize the M-PMV p12 domain's role in Gag-Gag interaction.
  • To identify functionally equivalent regions in the mouse mammary tumor virus (MMTV) Gag polyprotein.
  • To elucidate the molecular mechanisms underlying Gag self-association in betaretroviruses.

Main Methods:

  • Yeast two-hybrid system to assess Gag polyprotein interactions.
  • Comparative analysis of M-PMV and MMTV Gag protein domains.
  • Investigating protein-protein interaction domains within viral polyproteins.

Main Results:

  • Both M-PMV and MMTV Gag polyproteins interact strongly, primarily via their CA-NC regions.
  • M-PMV Gag self-association is significantly mediated by the N-terminal p12 domain.
  • MMTV Gag self-association involves multiple domains contributing to CA-NC interaction, rather than a single dominant domain.

Conclusions:

  • M-PMV Gag relies predominantly on its p12 domain for auxiliary interactions during capsid assembly.
  • MMTV Gag self-association is a complex process involving the synergistic action of several protein regions.
  • These findings highlight distinct strategies employed by betaretroviruses for Gag polyprotein interactions and viral assembly.

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