Characterization of the Bas-Congo virus glycoprotein and its function in pseudotyped viruses

J Virol. 2013 Sep;87(17):9558-68. doi: 10.1128/JVI.01183-13. Epub 2013 Jun 19.

Abstract

Bas-Congo virus (BASV) is a novel rhabdovirus recently identified from a patient with acute hemorrhagic fever in the Bas-Congo province of the Democratic Republic of Congo (DRC). Here we show that the BASV glycoprotein (BASV-G) can be successfully used to pseudotype glycoprotein-deficient vesicular stomatitis virus (VSV), allowing studies of BASV-G-driven membrane fusion and viral entry into target cells without replication-competent virus. BASV-G displayed broad tissue and species tropism in vitro, and BASV-G-mediated membrane fusion was pH dependent. The conformational changes induced in BASV-G by acidification were fully reversible and did not lead to inactivation of the viral fusion protein. Our data combined with comparative sequence similarity analyses suggest that BASV-G shares structural and functional features with other rhabdovirus glycoproteins and falls into the group of class III viral fusion proteins. However, activation of BASV-G-driven fusion required a lower pH and higher temperatures than did VSV-G-mediated fusion. Moreover, in contrast to VSV-G, mature BASV-G in VSV pseudotypes consists of a mixture of high-mannose and complex glycans that enables it to bind to certain C-type lectins, thereby enhancing its attachment to target cells. Taken together, the results presented in this study will facilitate future investigations of BASV-G-mediated cell entry and its inhibition in the absence of an infectious cell culture assay for BASV and at lower biosafety levels. Moreover, serology testing based on BASV-G pseudotype neutralization can be used to uncover the prevalence and importance of BASV as a potential novel human pathogen in the DRC and throughout Central Africa.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Congo
  • Cricetinae
  • Humans
  • Membrane Fusion
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / physiology
  • Mice
  • Molecular Sequence Data
  • Rhabdoviridae / classification
  • Rhabdoviridae / genetics
  • Rhabdoviridae / physiology*
  • Rhabdoviridae Infections / virology*
  • Sequence Homology, Amino Acid
  • Viral Envelope Proteins / genetics
  • Viral Envelope Proteins / physiology*
  • Virus Internalization

Substances

  • G protein, vesicular stomatitis virus
  • Membrane Glycoproteins
  • Viral Envelope Proteins