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Deletions in the fifth alpha helix of HIV-1 matrix block virus release

Bridget Sanford1, Yan Li1, Connor J Maly1

  • 1Department of Medical Microbiology and Immunology, Creighton University, 2500 California Plaza, Omaha, NE 68178, USA.

Virology
|September 14, 2014
PubMed

Insights

The matrix (MA) protein

Area of Science:

  • Virology and Molecular Biology
  • Structural Biology

Background:

  • The matrix (MA) protein is essential for HIV-1 replication.
  • MA is the N-terminal component of the Gag structural protein, containing five alpha-helices (α1-α5).

Purpose of the Study:

  • To investigate the role of the α5 helix in the MA protein during HIV-1 replication.
  • To determine how structural changes in α5 affect virus release and infectivity.

Main Methods:

  • Deletion mutagenesis of the MA protein's α5 helix.
  • Analysis of viral particle release using electron microscopy and immunoblots.
  • Assessment of membrane association, multimerization, and infectivity of viral mutants.

Main Results:

  • Deletions in the N-terminus of α5, even as small as three amino acids, impaired virus release.
  • A specific mutant (MA∆96-120) showed particles tethered by membranous stalks and inhibited wild-type particle release.
  • While some mutants showed altered processing, MA∆96-120 retained membrane association and multimerization.
  • Alanine scanning mutations in this region did not affect release but resulted in poorly infectious virions.

Conclusions:

  • Structural ablation of the α5 helix in the HIV-1 MA protein significantly inhibits virus release.
  • The α5 helix is crucial for proper viral particle budding and release from host cells.
  • Disruptions in α5 impact viral particle assembly and egress, affecting overall viral replication.
Keywords:
Deletion mutagenesisHIV-1 assemblyHIV-1 buddingMatrixNEDD4L

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