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A High-throughput Cre-Lox Activated Viral Membrane Fusion Assay to Identify Inhibitors of HIV-1 Viral Membrane Fusion
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Coreceptor-dependent inhibition of the cell fusion activity of simian immunodeficiency virus Env proteins

C Yang1, Q Yang, R W Compans

  • 1Department of Microbiology and Immunology, Emory University School of Medicine, Atlanta, Georgia 30322, USA.

Journal of Virology
|June 14, 2000
PubMed

Insights

The R peptide sequence inhibits fusion for simian immunodeficiency virus (SIV)-murine leukemia virus (MuLV) chimeric envelope proteins. However, this inhibition is reduced when cells express the CCR5 coreceptor, indicating differential effects based on coreceptor type.

Area of Science:

  • Virology
  • Molecular Biology
  • Cell Biology

Background:

  • The cytoplasmic tail (R peptide) of the murine leukemia virus (MuLV) envelope (Env) protein regulates fusion activity.
  • Simian immunodeficiency virus (SIV) utilizes various cellular coreceptors for cell entry.
  • Previous studies indicated the R peptide inhibits fusion in SIV-MuLV chimeric Env proteins.

Purpose of the Study:

  • To investigate the fusion activity of SIV and SIV-MuLV chimeric Env proteins.
  • To determine the effect of different cellular coreceptors on R peptide-mediated fusion regulation.
  • To understand the differential impact of the R peptide on SIV Env fusion using alternative coreceptors.

Main Methods:

  • Transfection of HeLa cells with SIV or SIV-MuLV chimeric Env protein genes.
  • Cocultivation of transfected HeLa cells with target cells expressing specific SIV coreceptors (Gpr15 or CCR5).
  • Assessment of viral fusion activity based on Env protein expression and coreceptor presence.

Main Results:

  • The R peptide sequence inhibited fusion with CEMx174 cells and Ghost Gpr15 cells (Gpr15 coreceptor).
  • A significant level of fusion was observed when using Ghost CCR5 cells (CCR5 coreceptor).
  • The R peptide's inhibitory effect on SIV Env fusion varied depending on the target cell's coreceptor.

Conclusions:

  • The R peptide sequence exhibits differential regulation of SIV Env fusion activity.
  • Coreceptor usage significantly influences the inhibitory effect of the R peptide.
  • These findings highlight the complex interplay between viral Env proteins, coreceptors, and fusion regulation in SIV entry.

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