FIG. 2.

Adventitious mutations detected in the editing site of the EV GP ORF in recovered HPIV3/EboGP and HPIV3/EboGP-NP viruses. The top line shows the positive-sense sequence of part of the editing site in the unedited version of EV GP mRNA, with encoded amino acids (a.a.) and their sequence positions in GP indicated and the homo-oligomeric A tract underlined. The next line shows the edited version of the mRNA containing a tract of eight A residues; this is the version that initially was inserted into the HPIV3 vector but proved to be unstable. The next four lines illustrate sequences from recovered viruses containing a nucleotide substitution or a nucleotide deletion that disrupts this run of eight A residues. The sequence at the bottom is an engineered mutant version of the edited mRNA that contains two A→G substitutions that interrupt the run of eight A residues without affecting amino acid coding; this version was used to make the second set of HPIV3/EboGP and HPIV3/EboGP-NP viruses that were used in this study.