Picornavirus IRES elements: RNA structure and host protein interactions

•Picornavirus infection triggers host factors modification impacting on cellular gene expression.•Picornavirus RNA translation is governed by IRES elements which are resistant to cap-dependent inactivation.•Diversity of picornavirus IRES RNA structural organization.•Implication of host RNA-binding proteins in picornavirus protein synthesis.

Internal ribosome entry site (IRES) elements were discovered in picornaviruses. These elements are cis-acting RNA sequences that adopt diverse three-dimensional structures and recruit the translation machinery using a 5′ end-independent mechanism assisted by a subset of translation initiation factors and various RNA binding proteins termed IRES transacting factors (ITAFs). Many of these factors suffer important modifications during infection including cleavage by picornavirus proteases, changes in the phosphorylation level and/or redistribution of the protein from the nuclear to the cytoplasm compartment. Picornavirus IRES are amongst the most potent elements described so far. However, given their large diversity and complexity, the mechanistic basis of its mode of action is not yet fully understood. This review is focused to describe recent advances on the studies of RNA structure and RNA-protein interactions modulating picornavirus IRES activity.