6p4g
Structure of a mammalian small ribosomal subunit in complex with the Israeli Acute Paralysis Virus IRES (Class 1)
Structural highlights
FunctionRS12_RABIT Part of the small subunit (SSU) processome, first precursor of the small eukaryotic ribosomal subunit (PubMed:23873042, PubMed:25601755, PubMed:26245381, PubMed:27863242, PubMed:30517857). During the assembly of the SSU processome in the nucleolus, many ribosome biogenesis factors, an RNA chaperone and ribosomal proteins associate with the nascent pre-rRNA and work in concert to generate RNA folding, modifications, rearrangements and cleavage as well as targeted degradation of pre-ribosomal RNA by the RNA exosome (PubMed:23873042, PubMed:25601755, PubMed:26245381, PubMed:27863242, PubMed:30517857). Subunit of the 40S ribosomal complex (PubMed:23873042, PubMed:25601755, PubMed:26245381, PubMed:27863242, PubMed:30517857).[1] [2] [3] [4] [5] Publication Abstract from PubMedColony collapse disorder (CCD) is a multi-faceted syndrome decimating bee populations worldwide, and a group of viruses of the widely distributed Dicistroviridae family have been identified as a causing agent of CCD. This family of viruses employs non-coding RNA sequences, called internal ribosomal entry sites (IRESs), to precisely exploit the host machinery for viral protein production. Using single-particle cryo-electron microscopy (cryo-EM), we have characterized how the IRES of Israeli acute paralysis virus (IAPV) intergenic region captures and redirects translating ribosomes toward viral RNA messages. We reconstituted two in vitro reactions targeting a pre-translocation and a post-translocation state of the IAPV-IRES in the ribosome, allowing us to identify six structures using image processing classification methods. From these, we reconstructed the trajectory of IAPV-IRES from the early small subunit recruitment to the final post-translocated state in the ribosome. An early commitment of IRES/ribosome complexes for global pre-translocation mimicry explains the high efficiency observed for this IRES. Efforts directed toward fighting CCD by targeting the IAPV-IRES using RNA-interference technology are underway, and the structural framework presented here may assist in further refining these approaches. The Israeli acute paralysis virus IRES captures host ribosomes by mimicking a ribosomal state with hybrid tRNAs.,Acosta-Reyes F, Neupane R, Frank J, Fernandez IS EMBO J. 2019 Oct 14:e102226. doi: 10.15252/embj.2019102226. PMID:31609474[6] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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