FIG. 4.

Mengovirus replicon pMluz. (A) Within this cDNA, the 3′ half of the viral 1C region, the complete 1D region, and the first two codons of the viral 2A region were replaced in-frame by the firefly luciferase gene. Additional cDNAs differed from pMluz in that they contained separate deletions of 3′ UTR stems I, II, or III. (B) Luciferase activity in transfected HeLa cells was determined as described in Materials and Methods. All samples (20 μl of lysate) were prepared and assayed in parallel.