FIG. 3.

Deletion constructs and their corresponding RSS activities. (A) Diagrammatic representation of the various SARS-CoV 7a mutations used in this study. The numbers at the ends of the deletions refer to amino acids. The stop codon (*) and the start codon (Φ) introduced during cloning are indicated. The dotted line indicates the transcript that failed to translate due to a premature stop codon. The yellow rectangle shows the 6-amino-acid mapped domain responsible for RSS activity. Relative RSS activity exhibited by each 7a construct (wt, point mutation, and deletions) are shown on the extreme right, where ++++ represents the highest level of RSS activity, +++ a medium level, ++ a low level, and − the lowest level. (B) Results from the reversal-of-silencing assay, with various deletions of 7a performed to map the suppressor domain in the protein.