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Characterization of R peptide of murine leukemia virus envelope glycoproteins in syncytium formation and entry

Y Kubo1, C Tominaga, H Yoshii

  • 1Department of AIDS Research, Institute of Tropical Medicine, Nagasaki University, Nagasaki, Japan. yoshinao@net.nagasaki-u.ac.jp

Archives of Virology
|September 14, 2007
PubMed

Insights

Cleavage of the R peptide from murine leukemia virus (MLV) envelope protein (Env) is crucial for viral entry. Efficient R peptide cleavage enhances MLV vector transduction efficiency across various MLV types.

Area of Science:

  • Retroviral biology
  • Molecular virology
  • Biochemistry

Background:

  • The C-terminal R peptide of ecotropic murine leukemia virus (MLV) envelope protein (Env) regulates membrane fusion.
  • Cleavage of the R peptide during virion maturation is essential for activating fusogenicity and enabling viral entry.

Purpose of the Study:

  • To investigate the role of R peptide cleavage in the fusogenicity and transduction efficiency of different MLV Env proteins.
  • To determine the importance of hydrophobic residues near the cleavage site for R peptide-mediated fusion inhibition.
  • To explore the necessity of R peptide cleavage for amphotropic, polytropic, and xenotropic MLV vector transduction.

Main Methods:

  • Analysis of fusogenicity and transduction efficiency of mutant MLV Env proteins.
  • Site-directed mutagenesis to alter hydrophobic amino acid residues around the R peptide cleavage site.
  • Comparative assessment of Env proteins with and without the R peptide.

Main Results:

  • Hydrophobic amino acid residues near the R peptide cleavage site are critical for inhibiting membrane fusion.
  • Env complexes containing the R peptide exhibit reduced fusogenicity and transduction compared to R-peptide-truncated Env alone.
  • R peptide cleavage is essential for efficient transduction mediated by ecotropic, amphotropic, polytropic, and xenotropic MLV vectors.
  • Xenotropic and polytropic MLV R-peptide-truncated Env proteins show significantly lower fusogenicity than ecotropic and amphotropic counterparts.

Conclusions:

  • Efficient R peptide cleavage is a prerequisite for effective MLV vector transduction across multiple MLV types.
  • Understanding the R peptide's role in fusion inhibition and cleavage is vital for developing improved MLV vectors.
  • These findings contribute to a deeper understanding of retroviral entry mechanisms.

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