FIG. 1.

Northern blot analysis of TGEV defective minigenomes. The analysis of the TGEV PUR46-MAD strain RNAs alone (lane a) or after 40 passages at a high multiplicity of infection (50 to 100 PFU/cell), that resulted in the selection of three defective RNAs (DI-A, DI-B, and DI-C) (lane b), was performed by Northern blotting with a probe specific for the 3′ UTR. Numbers and letters on the left indicate the position of the genomic (gRNA) and viral mRNAs. S, Spike; 3a, gene 3a; E, envelope; M, membrane; N, nucleoprotein; 7, gene 7. Arrows and numbers on the right indicate the position and approximate size of the defective RNAs.