Internal ribosome entry sites of viral and cellular RNAs
ABSTRACT In recent years mechanism of internal initation of translation in eukaryotic cells commands the attention of molecular biologists
in increasing frequency. Ten years ago, experiments with picornaviruses demonstrated the ability of 40S ribosomal subunits
to bind to nucleotide sequences localized far from the 5′ ends of RNA molecules, and since then numerous viral and even cellular
RNAs were shown to be capable of internal initiation of translation. In the present survey, data on the localization, structure,
and functional load of these internal ribosome entry sites (IRES elements) of viral and cellular RNAs, as well as on proteins
capable of strong and highly specific binding to IRES elements, are discussed. A conclusion is that a unified model of structure
and fuctioning of viral and cellular IRES elements cannot be suggested.