FIG. 6.

Leader-containing subgenomic transcripts are present in cultures infected with TGEV VRPs. Intracellular RNA was isolated from cell cultures infected with pass 0 supernatants and used as a template for RT-PCR to detect leader-containing GFP, M, and N subgenomic transcripts using a 5′ leader primer (TGEV-L) and 3′ primers located just downstream of each respective gene. (A) An appropriately sized amplicon of ∼850 bp was generated (indicated by an arrow), corresponding to leader-containing transcripts encoding GFP (lane 1). Lane 2 shows a 1-kb ladder. (B) In addition, amplicons of ∼900 bp and ∼1.2 kb were generated, corresponding to leader-containing M and N gene mRNA transcripts, respectively. The arrows correspond to leader-containing M (lane 2) or N (lane 3) transcripts. A 1-kb ladder is shown in lane 1.