IRES

This animation compares the structure of ribosome complexes in either IRES-mRNA (Internal RIbosome Entry Sequence) or capped-mRNA conformations. Video by: Stylus Visuals Wiki text info: An internal ribosome entry site, abbreviated IRES, is a nucleotide sequence that allows for translation initiation in the middle of a messenger RNA (mRNA) sequence as part of the greater process of protein synthesis. Usually, in eukaryotes, translation can only be initiated at the 5' end of the mRNA molecule, since 5' cap recognition is required for the assembly of the initiation complex.