title: Role of the cytoplasmic tail domains of Bunyamwera orthobunyavirus glycoproteins Gn and Gc in virus assembly and morphogenesis.
abstract: The M RNA genome segment of Bunyamwera virus (BUNV), the prototype of the Bunyaviridae family, encodes a precursor polyprotein that is proteolytically cleaved to yield two structural proteins, Gn and Gc, and a nonstructural protein called NSm. Gn and Gc are type I integral transmembrane glycoproteins. The Gn protein contains a predicted cytoplasmic tail (CT) of 78 residues, and Gc has a shorter CT of 25 residues. Little is known about the role of the Gn and Gc CT domains in the virus replication cycle. We generated a series of mutant glycoprotein precursor constructs containing either deletions or alanine substitutions in the CT domains of Gn and Gc. We examined the effects of these mutations on glycoprotein maturation, cell surface expression, and low pH-induced syncytium formation. In addition, the effects of these mutations were also assessed using a reverse genetics-based virus assembly assay and a virus rescue system. Our results show that the CT domains of both Gn and Gc play crucial roles in BUNV-mediated membrane fusion, virus assembly, and morphogenesis.
authors.affiliation: Centre for Biomolecular Sciences, School of Biology, University of St. Andrews, North Haugh, St. Andrews, Scotland, United Kingdom.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Shi
authors.forename: Alain
authors.initials: A
authors.lastname: Kohl
authors.forename: Ping
authors.initials: P
authors.lastname: Li
authors.forename: Richard M
authors.initials: RM
authors.lastname: Elliott
mesh_terms: D019943:Amino Acid Substitution; D000818:Animals; D002042:Bunyamwera virus / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D002522:Chlorocebus aethiops; D006224:Cricetinae; D015726:Giant Cells / Q000378:metabolism / Q000648:ultrastructure / Q000821:virology; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D011498:Protein Precursors / Q000235:genetics / Q000378:metabolism*; D017434:Protein Structure, Tertiary / Q000235:genetics; D014709:Vero Cells; D015678:Viral Structural Proteins / Q000235:genetics / Q000378:metabolism*; D019065:Virus Assembly / Q000502:physiology*
chemical_list: D006023:Glycoproteins; D011498:Protein Precursors; D015678:Viral Structural Proteins