GP mRNA of Ebola virus is edited by the Ebola virus polymerase and by T7 and vaccinia virus polymerases.

The glycoprotein gene of Ebola virus contains a translational stop codon in the middle, thus preventing synthesis of full-length glycoprotein. Twenty percent of the mRNA isolated from Ebola virus-infected cells was shown to be edited, containing one additional nontemplate A in a stretch of seven consecutive A residues. Only the edited mRNA species encoded full-length glycoprotein, whereas the exact copies of the viral template coded for a smaller secreted glycoprotein. Expression of the glycoprotein by an in vitro transcription/translation system, by the vaccinia virus/T7 polymerase system, and by recombinant vaccinia virus revealed that full-length glycoprotein was synthesized not only when the edited glycoprotein gene (8A's) was used as a template for T7 and vaccinia virus polymerases, but also when the nonedited (genomic) glycoprotein gene was used. Analysis of mRNA produced by T7 and vaccinia virus polymerase from the 7A's construct revealed that 1-5% contained alterations at the same site that was also edited by the Ebola virus polymerase. Our data indicate that the editing site in the Ebola virus glycoprotein gene is recognized not only by Ebola virus polymerase but also by DNA-dependent RNA polymerases of different origin.