title: A new Ebola virus nonstructural glycoprotein expressed through RNA editing.
abstract: Ebola virus (EBOV), an enveloped, single-stranded, negative-sense RNA virus, causes severe hemorrhagic fever in humans and nonhuman primates. The EBOV glycoprotein (GP) gene encodes the nonstructural soluble glycoprotein (sGP) but also produces the transmembrane glycoprotein (GP₁,₂) through transcriptional editing. A third GP gene product, a small soluble glycoprotein (ssGP), has long been postulated to be produced also as a result of transcriptional editing. To identify and characterize the expression of this new EBOV protein, we first analyzed the relative ratio of GP gene-derived transcripts produced during infection in vitro (in Vero E6 cells or Huh7 cells) and in vivo (in mice). The average percentages of transcripts encoding sGP, GP₁,₂, and ssGP were approximately 70, 25, and 5%, respectively, indicating that ssGP transcripts are indeed produced via transcriptional editing. N-terminal sequence similarity with sGP, the absence of distinguishing antibodies, and the abundance of sGP made it difficult to identify ssGP through conventional methodology. Optimized 2-dimensional (2D) gel electrophoresis analyses finally verified the expression and secretion of ssGP in tissue culture during EBOV infection. Biochemical analysis of recombinant ssGP characterized this protein as a disulfide-linked homodimer that was exclusively N glycosylated. In conclusion, we have identified and characterized a new EBOV nonstructural glycoprotein, which is expressed as a result of transcriptional editing of the GP gene. While ssGP appears to share similar structural properties with sGP, it does not appear to have the same anti-inflammatory function on endothelial cells as sGP.
authors.affiliation: Department of Medical Microbiology, University of Manitoba, Public Health Agency of Canada, Winnipeg, Manitoba, Canada.
authors.forename: Masfique
authors.initials: M
authors.lastname: Mehedi
authors.forename: Darryl
authors.initials: D
authors.lastname: Falzarano
authors.forename: Jochen
authors.initials: J
authors.lastname: Seebach
authors.forename: Xiaojie
authors.initials: X
authors.lastname: Hu
authors.forename: Michael S
authors.initials: MS
authors.lastname: Carpenter
authors.forename: Hans-Joachim
authors.initials: HJ
authors.lastname: Schnittler
authors.forename: Heinz
authors.initials: H
authors.lastname: Feldmann
mesh_terms: D000818:Animals; D002460:Cell Line; D029043:Ebolavirus / Q000235:genetics*; D015180:Electrophoresis, Gel, Two-Dimensional; D020869:Gene Expression Profiling; D015967:Gene Expression Regulation, Viral; D006023:Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D006801:Humans; D008562:Membrane Glycoproteins / Q000096:biosynthesis* / Q000235:genetics; D051379:Mice; D017393:RNA Editing; D014763:Viral Matrix Proteins / Q000096:biosynthesis* / Q000235:genetics; D017361:Viral Nonstructural Proteins / Q000096:biosynthesis* / Q000235:genetics
chemical_list: D006023:Glycoproteins; D008562:Membrane Glycoproteins; D014763:Viral Matrix Proteins; D017361:Viral Nonstructural Proteins; C110614:transmembrane glycoprotein, Ebola virus