Initiation of translation by cricket paralysis virus IRES requires its translocation in the ribosome.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 24792965.
- Also identified by DOI 10.1016/j.cell.2014.04.015 and PMC identifier 4017093.
- Licence recorded as CC BY.
- The licence permits redistribution, so the abstract is shown in full and the full text is available from the publisher.
Abstract
The cricket paralysis virus internal ribosome entry site (CrPV-IRES) is a folded structure in a viral mRNA that allows initiation of translation in the absence of any host initiation factors. By using recent advances in single-particle electron cryomicroscopy, we have solved the structure of CrPV-IRES bound to the ribosome of the yeast Kluyveromyces lactis in both the canonical and rotated states at overall resolutions of 3.7 and 3.8 Å, respectively. In both states, the pseudoknot PKI of the CrPV-IRES mimics a tRNA/mRNA interaction in the decoding center of the A site of the 40S ribosomal subunit. The structure and accompanying factor-binding data show that CrPV-IRES binding mimics a pretranslocation rather than initiation state of the ribosome. Translocation of the IRES by elongation factor 2 (eEF2) is required to bring the first codon of the mRNA into the A site and to allow the start of translation.
Medical subject headings
- Dicistroviridae
- Kluyveromyces
- Peptide Chain Initiation, Translational
- RNA, Messenger
- RNA, Viral
- Ribosomes