Functional analysis of the Bunyamwera orthobunyavirus Gc glycoprotein.
The virion glycoproteins Gn and Gc of Bunyamwera orthobunyavirus (family Bunyaviridae) are encoded by the M RNA genome segment and have roles in both viral attachment and membrane fusion. To investigate further the structure and function of the Gc protein in viral replication, we generated 12 mutants that contain truncations from the N terminus. The effects of these deletions were analysed with regard to Golgi targeting, low pH-dependent membrane fusion, infectious virus-like particle (VLP) formation and virus infectivity. Our results show that the N-terminal half (453 residues) of the Gc ectodomain (909 residues in total) is dispensable for Golgi trafficking and cell fusion. However, deletions in this region resulted in a significant reduction in VLP formation. Four mutant viruses that contained N-terminal deletions in their Gc proteins were rescued, and found to be attenuated to different degrees in BHK-21 cells. Taken together, our data indicate that the N-terminal half of the Gc ectodomain is dispensable for replication in cell culture, whereas the C-terminal half is required to mediate cell fusion. A model for the domain structure of the Gc ectodomain is proposed.
Shi
Xiaohong
X
Centre for Biomolecular Sciences, School of Biology, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland, UK.
Goli
Josthna
J
Centre for Biomolecular Sciences, School of Biology, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland, UK.
Clark
Gordon
G
Centre for Biomolecular Sciences, School of Biology, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland, UK.
Brauburger
Kristina
K
Centre for Biomolecular Sciences, School of Biology, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland, UK.
Elliott
Richard M
RM
Centre for Biomolecular Sciences, School of Biology, University of St Andrews, North Haugh, St Andrews KY16 9ST, Scotland, UK.
D000818:Animals; D002042:Bunyamwera virus / Q000235:genetics / Q000378:metabolism*; D002459:Cell Fusion; D002460:Cell Line; D006224:Cricetinae; D015967:Gene Expression Regulation, Viral / Q000502:physiology*; D006863:Hydrogen-Ion Concentration; D009154:Mutation; D021381:Protein Transport; D014759:Viral Envelope Proteins / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly
D014759:Viral Envelope Proteins