FIG. 1.

Schematic diagram of replicon and full-length poliovirus genomes used in this study. Open circle, wt PV-cre(2C). Arrows, positions of unique restriction endonuclease sites engineered for the insertion of the second copy of cre of various origins. In rescue experiments, the native cre(2C) was inactivated through a point mutation (A₅C) in the conserved AAA sequence of the PV-cre loop (X) and a second copy of cre (filled hairpin loop) from poliovirus, HRV2, or HRV14 or an artificial cre was inserted at locations indicated by arrows.