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Retroviral Scanning: Mapping MLV Integration Sites to Define Cell-specific Regulatory Regions
10:10

Retroviral Scanning: Mapping MLV Integration Sites to Define Cell-specific Regulatory Regions

Published on: May 28, 2017

The retrovirus MA and PreTM proteins follow immature MLV cores

Klaus B Andersen1

  • 1Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Universitetsparken 2, DK2100 Copenhagen, Denmark. Kba@sund.ku.dk

Virus Research
|May 7, 2013
PubMed

Insights

Moloney Murine Leukemia Virus (MoMLV) immature cores bind mature Gag proteins, with matrix (MA) and transmembrane (TM) proteins showing significant association. These interactions are primarily protein-protein, not lipid-based.

Area of Science:

  • Virology
  • Molecular Biology
  • Structural Biology

Background:

  • The immature core of Moloney Murine Leukemia Virus (MoMLV) comprises the Gag polyprotein (PrGag) and viral RNA (vRNA).
  • Immature MoMLV cores are detergent-resistant, unlike mature Gag cores formed after PrGag cleavage.

Purpose of the Study:

  • To investigate the composition and binding interactions of immature MoMLV PrGag cores.
  • To characterize the binding of mature Gag proteins and transmembrane (TM) proteins to PrGag cores.

Main Methods:

  • Mild detergent treatment to isolate MoMLV PrGag cores and core-like complexes from infected cells.
  • Analysis of protein and lipid content of detergent-treated samples.
  • RNase A treatment to assess RNA-protein interactions.

Main Results:

  • Mature Gag proteins (MA, CA, NC) bind to PrGag cores with varying affinities: MA (13-20%), CA (3-5%), NC (5-15%).
  • NC binding is reduced by RNase A, indicating viral RNA interaction.
  • Transmembrane protein (TM) binding is low (~5%), but PreTM (TM with R peptide) binding is high (65%).
  • Minimal lipid content suggests direct protein-protein interactions mediate binding.

Conclusions:

  • Immature MoMLV cores exhibit specific protein-protein interactions with mature Gag components and TM proteins.
  • The cytoplasmic R peptide tail of TM significantly enhances its binding to PrGag cores.
  • Binding is predominantly mediated by protein interactions rather than lipid rafts.

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