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Assembly and Purification of Prototype Foamy Virus Intasomes
10:20

Assembly and Purification of Prototype Foamy Virus Intasomes

Published on: March 19, 2018

Foamy retrovirus integrase contains a Pol dimerization domain required for protease activation

Eun-Gyung Lee1, Jacqueline Roy, Dana Jackson

  • 1Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.

Journal of Virology
|December 3, 2010
PubMed

Insights

Foamy retrovirus (FV) protease (PR) activity and Pol precursor packaging require integrase (IN). Introducing a dimerization motif restored PR activity but not virion packaging, suggesting IN is essential for Pol dimerization and PR activation.

Area of Science:

  • Virology
  • Molecular Biology
  • Retroviral Research

Background:

  • Foamy retroviruses (FV) differ from orthoretroviruses in Pol precursor synthesis and processing.
  • FV Pol precursor is cleaved once by protease (PR) into PR-reverse transcriptase (RT) and integrase (IN) subunits.
  • Only the uncleaved Pol precursor is incorporated into virions, and FV PR requires dimerization for activity.

Purpose of the Study:

  • To investigate the role of integrase (IN) in foamy retrovirus (FV) Pol precursor processing and virion packaging.
  • To determine if restoring protease (PR) dimerization can rescue PR activity and Pol processing in IN-deficient mutants.

Main Methods:

  • Construction and analysis of IN truncation mutants with a leucine zipper (zip) dimerization motif.
  • Assessment of protease (PR) activity and Pol precursor processing in cells expressing these mutants.
  • Evaluation of Gag cleavage and Pol incorporation into virions.

Main Results:

  • Introduction of a leucine zipper (zip) motif in an IN truncation mutant restored PR activity and Pol processing in cells.
  • These zip mutants failed to cleave Gag or incorporate the Pol precursor into virions.
  • The results indicate that IN is necessary for PR activity, even when dimerization is artificially restored.

Conclusions:

  • Integrase (IN) is crucial for foamy retrovirus (FV) Pol precursor dimerization.
  • Pol dimerization, mediated by IN, is essential for creating a functional protease (PR) active site.
  • IN's role extends beyond its enzymatic function, influencing PR activation and virion packaging.

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