Identification of regions on the fusion protein of human parainfluenza virus type 2 which are required for haemagglutinin-neuraminidase proteins to promote cell fusion

J Gen Virol. 1998 Feb;79 ( Pt 2):279-89. doi: 10.1099/0022-1317-79-2-279.


Using a plasmid expression system in HeLa cells, we have previously shown that the fusion (F) protein of simian virus 41 (SV-41) induces cell fusion when coexpressed with the haemagglutinin-neuraminidase (HN) protein of human parainfluenza virus type 2 (PIV-2), while the PIV-2 F protein does not induce cell fusion with the SV-41 HN protein. In the present study, we found that the PIV-2 F protein induced extensive cell fusion with the HN protein of mumps virus (MuV), whereas the SV-41 F protein did not. Chimaeric analyses of the F proteins of PIV-2 and SV-41 identified two regions (designated M1 and M2) on the PIV-2 F protein, either of which was necessary for chimaeric F proteins to show fusogenic activity with the MuV HN protein. Subsequently, two additional regions (P1 and P2) were identified on the PIV-2 F protein, both of which were necessary for chimaeric F proteins to prevent induction of cell fusion with the SV-41 HN protein. Consequently, it was proved that a given chimaeric F protein, harbouring regions P1 and P2 together with either of region M1 or M2, induced cell fusion specifically with HN proteins of PIV-2 and MuV, the same as the PIV-2 F protein. Region M2 was located at the membrane proximal end of the PIV-2 F1 ectodomain, while regions P1, M1 and P2 clustered together in the middle of the ectodomain. These regions on the PIV-2 F protein may be involved in a putative functional interaction with HN proteins, which is considered to be a prerequisite for cell fusion.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Fusion*
  • Cell Line
  • Cell Membrane / physiology
  • Chlorocebus aethiops
  • HN Protein / physiology*
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Parainfluenza Virus 2, Human / physiology*
  • Recombinant Fusion Proteins / biosynthesis
  • Recombinant Fusion Proteins / chemistry
  • Rubulavirus / physiology
  • Sequence Alignment
  • Sequence Homology, Amino Acid
  • Transfection
  • Viral Fusion Proteins / biosynthesis
  • Viral Fusion Proteins / chemistry
  • Viral Fusion Proteins / physiology*


  • HN Protein
  • Recombinant Fusion Proteins
  • Viral Fusion Proteins