FIG. 9.

RNase protection assay of M mRNAs in influenza C virus M gene-transfected cells coexpressing influenza C virus NS1 protein. (A) pME18S-CM (0.5 μg) was introduced into COS-1 cells either together with 0.5, 1.0, or 2.0 μg of pME18S-CNS1 (right three lanes) or without pME18S-CNS1 (CM lane) and analyzed by RNase protection assay using an antisense M-specific RNA probe. The probe lane contains the undigested probe (upper panel). The expression of the C/NS1 protein in cells transfected as described above was analyzed by RIP with anti-GST/NS1 serum (lower panel). (B) Ratios of 5′ spliced to unspliced M mRNA in the transfected cells shown in panel A. (C) The ratios of 5′ spliced to unspliced M mRNA in COS-1 cells cotransfected with pME18S-CM and the pME18S vector as a control (CM+vector bar) or pME18S-CM and pME18S-CNS1 (CM+CNS1 bar) in four independent RNase protection assay experiments and cotransfected with pME18S-CM and pME18S-ANS1 (CM+ANS1 bar) in three independent experiments were compared.