Source:http://linkedlifedata.com/resource/umls/id/C1512886
NCI: Internal ribosome entry site (IRES) is a translational cis-acting element that directs ribosomes to the start codon by a cap-independent mechanism. IRESs are usually about 450 nucleotides in length and were first identified in picornavirus RNAs. IRESs can fold into a stable secondary hairpin structure to be incompatible with efficient translation by ribosomal scanning. (NCI)