FIG. 3.

Localization of signals responsible for transcriptional activation of mRNA N. (A) Scheme showing the genetic structure of TGEV-derived replicons. The TGEV genome and the genetic structure of TGEV-derived replicon REP-1 are shown in the first and second lines, respectively. TGEV genes are represented by letters above the boxes. The scheme of different mutant replicons generated to localize the signals responsible for transcriptional activation of sg mRNA N is shown at the bottom, and their names are indicated to the left. Numbers indicate distances in nucleotides upstream of CS-N. Distal 5′ TRS-N includes nt −800 to −120 upstream of the CS of the N gene (larger black box). Deletion mutants from this region are represented with smaller black boxes. 5′ TRS-N represents the first 120 nt upstream of the CS of the N gene (dark gray boxes). 3′ TRS-N includes the 3′ TRS of gene N. N indicates the N gene coding sequence (light gray boxes). 5′ TRS-3a includes the first 120 nt upstream of the CS of gene 3a. 3′ TRS-3a includes the 3′ TRS of gene 3a. UTR, untranslated region. (B) Quantification of sg mRNA N by real-time RT-PCR. The amounts of sg mRNA N expressed from each mutant replicon are shown relative to that of sg mRNA 7. The data are the averages of four independent experiments performed in triplicate in each case. Error bars represent standard deviations.