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An endoplasmic reticulum retrieval signal partitions human foamy virus maturation to intracytoplasmic membranes

P A Goepfert1, K Shaw, G Wang

  • 1Departments of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294-2170, USA. paulg@uab.edu

Journal of Virology
|August 10, 1999
PubMed

Insights

Human foamy virus (HFV) uses a dilysine motif to control where viral particles mature. This motif restricts budding to intracellular membranes but is not essential for infectivity.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • Foamy viruses (FVs) are unique retroviruses that mature at intracytoplasmic membranes.
  • The human foamy virus (HFV) envelope glycoprotein contains a dilysine (KKXX) motif, directing it to the endoplasmic reticulum (ER).

Purpose of the Study:

  • To investigate the function of the dilysine motif in HFV maturation and infectivity.
  • To determine the role of the ER retrieval signal in viral particle release and localization.

Main Methods:

  • Construction of infectious molecular clones of HFV with mutations in the dilysine motif.
  • Analysis of virion budding sites using electron microscopy (EM).
  • Quantification of viral particle release and infectivity titers.

Main Results:

  • Mutant HFV viruses exhibited both intracytoplasmic and plasma membrane budding, similar to wild-type.
  • Viruses lacking the dilysine signal showed increased budding at the plasma membrane.
  • Despite altered budding sites, mutant viruses retained infectivity and overall viral release levels were unchanged.

Conclusions:

  • The dilysine motif partially restricts the site of HFV maturation to intracellular membranes.
  • This motif is not essential for HFV infectivity, but influences the localization of viral budding.

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