Construction of plasmids to express HA-tagged muNS fusions.

aEach construct was designed to contain the portion of the M3 gene encoding the indicated amino acid residues of muNS.bFor each truncation construct, reverse primer (R) is in the reverse orientation relative to the coding strand, and the added stop codon and the added HA sequence are double underlined, and forward primer (F) is in the forward orientation relative to the coding strand, and the added start codon is double underlined. The EcoRI and XbaI restriction sites added near the 5′ end of each primer are single underlined.cEach construct was designed to express a truncated muNS protein comprising the indicated amino acid residues. In brackets, muNS regions as termed in results.