FIG. 3.

Characterization of influenza virus RNPs reconstituted in vivo. Influenza virus RNPs were reconstituted and purified as indicated in Fig. 1 and 2. (A) The RNA contained in the purified RNPs was isolated and analyzed by dot blot hybridization by using positive (vRNA)- and negative (cRNA)-polarity riboprobes. (B) Either cellular extracts from infected and transfected cells (EXTRACT) or purified RNPs (RNPs) were used for in vitro transcription by using ApG as primer. The in vitro product was purified, fractionated on oligo(dT) cellulose into poly(A)⁻ (A⁻) and poly(A)⁺ (A⁺) RNA, and analyzed on a sequencing gel. The products obtained when the complete reconstitution system was used are shown (COMP), as well as a control in which plasmid pT7NSΔCAT-RT was omitted (−RT). The arrowheads indicate the band corresponding to a full-length product. The stars show mRNA products deficient in polyadenylation. Numbers to the left refer to the mobility of molecular weight markers (in nucleotides).