Fig. 4.

Relative replication capacities of subgenomic ΔP1LucCRE RNAs containing the WT cre sequence (cre) or cres with base substitutions that alter the stability of potential base-pairing within the loop sequence. Replication competence was assessed as in Fig. 3b. Above each bar is shown the loop sequence tested. Mutated bases are circled; lines connecting bases indicate potential base-pair interactions. The mfold-predicted free energy of the structure predicted for the C14/C20 cre is -11.6 kcal/mol.