FIG. 1.

Diagram of the wild type (WT) and mutants containing copies of viral E/DLS sequences. DDN, DTN, ssN, and sTN are DDNΔPBS, DTNΔPBS, ssNΔPBS, and sTNΔPBS, respectively. A polyadenylation signal (polyA) and a PBS on fragment ΔP were mutated as described in Materials and Methods. Open triangles on ssNΔPBS and sTNΔPBS represent mutations introduced in the 5′ leader region. Schematics of the transcripts are shown at the right; the lines and circles represent viral RNA and the E/DLS region, respectively. The positions of the restriction endonuclease recognition sites in the constructs are indicated at the bottom.