FIG. 5.

Schematic representation of the NS gene construct. Boxes show open reading frames. (WTNS construct) A 246-amino-acid (aa) NS1 protein encoded by a colinear mRNA transcript of influenza C virus RNA segment 7 (NS gene) and a 182-amino-acid NS2 protein encoded by a spliced mRNA are expressed in cells transfected with pME18S-WTNS. (L20,45stop construct) Premature termination codons were introduced into Leu residues 20 and 45 of the N-terminal 62-amino-acid region, which is common to both the NS1 and NS2 coding regions, to eliminate the expression of both the NS1 and NS2 proteins. (CNS1 construct) Plasmid pME18S-CNS1, which expressed NS1 alone, was constructed by substituting the donor (214-GU-215) and acceptor (525-AG-526) for splicing into 214-GA-215 and 525-CG-526, respectively, thereby resulting in the abolition of transcription to the NS2 mRNA.