Breaking pseudo-twofold symmetry in the poliovirus 3′-UTR Y-stem by restoring Watson–Crick base pairs

Luciferase activity produced by wild-type and various poliovirus Y-stem mutants of the chimeric poliovirus luciferase replicon after transfection with in vitro transcribed RNA in the human HeLa cell. The symbols utilized to indicate each mutant are indicated in the inset. Closed symbols correspond to luciferase activity in the absence of GuHCL, open symbols to luciferase activity in the presence of GuHCl.