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An active site mutation increases the polymerase activity of the guinea pig-lethal Marburg virus

Alexander Koehler1, Larissa Kolesnikova1, Stephan Becker2,1

  • 1Institut für Virologie, Philipps-Universität Marburg, Hans-Meerwein-Str. 2, 35043 Marburg, Germany.

The Journal of General Virology
|July 25, 2016
PubMed

Insights

Marburg virus (MARV) adapted to guinea pigs shows increased replication due to mutations in its L polymerase and VP40 protein. These genetic changes enhance viral fitness, particularly in the new host, leading to a more lethal virus.

Area of Science:

  • Virology
  • Molecular Biology
  • Pathogen Adaptation

Background:

  • Marburg virus (MARV) causes severe human disease and transient illness in rodents.
  • MARV adaptation in guinea pigs led to a lethal variant with four amino acid changes.
  • Key mutations identified include VP40D184N and three in the viral RNA-dependent RNA polymerase (L).

Purpose of the Study:

  • To investigate the functional significance of MARV L polymerase mutations in human and guinea pig cells.
  • To understand the role of VP40D184N and L polymerase mutations in viral fitness and host adaptation.

Main Methods:

  • Sequential passaging of MARV in guinea pigs.
  • Site-directed mutagenesis of MARV L polymerase and VP40 proteins.
  • Assessing viral transcription and replication activity in human and guinea pig cells via co-expression assays.

Main Results:

  • A substitution at L position 741 (S741C) significantly enhanced transcription/replication activity in both cell types.
  • Substitutions D758A and A759D in L inhibited polymerase activity.
  • The S741C L mutant showed an eightfold higher polymerase activity in guinea pig cells compared to human cells when co-expressed with VP40D184N.

Conclusions:

  • The S741C substitution in MARV L polymerase is crucial for enhanced transcription and replication.
  • The combination of VP40D184N and L mutations confers a significant replicative advantage to MARV in guinea pig cells.
  • These findings elucidate mechanisms of MARV host adaptation and increased virulence.

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