Figure 2.
Predicted RNA secondary structure of the poliovirus 5′ NCR. Computer prediction and chemical and enzymatic RNA-structure probing were used to deduce a consensus RNA conformation. Conserved sequences among picornaviruses include a GNRA tetraloop (thought to function in tertiary interactions of RNAs and in protein binding), A/C_rich loops, and a pyrimidine-rich region just upstream of the conserved AUG codon. The IRES domain is boxed by red lines.