Two major outer envelope glycoproteins of Epstein-Barr virus are encoded by the same gene

Publisher Website
Google Scholar
Abstract
Two major outer envelope glycoproteins of Epstein-Barr virus, gp350 and gp220, are known to be encoded by 3.2- and 2.5-kilobase RNA species which map to the same DNA fragment. These RNA species have the same 5'' and 3'' ends. The larger RNA is encoded by a 2777-base DNA segment which is preceded by TATTAAA had AATAAA near its 3'' end, and contained a 2721-base open reading frame. The smaller RNA has one internal splice which maintains the same open reading frame. Translation of the 3.2- and 2.5-kilobase RNA species yielded proteins of 135 and 100 kilodaltons. The discrepancy between the 907 codons of the open reading frame and the 135-kilodalton size of the gp350 precursor is due to anomalous behavior of the protein in gel electrophoresis, since a protein translated from most of the Epstein-Barr virus open reading frame in Escherichia coli had similar properties. Antisera raised in rabbits to the protein expressed in E. coli specifically immunoprecipitated gp350 and gp220, confirming the mapping and sequencing results, and the translational reading frame. The rabbit antisera also reacted with the plasma membranes of cells that were replicating virus and neturalized virus, particularly after the addition of complement. This is the first demonstration that the primary amino acid sequence of gp350 and gp220 has epitopes which can induce neutralizing antibody. A model is proposed for the gp350 protein based on the theoretical analysis of its primary sequence.