Fiche publication
Date publication
septembre 2017
Journal
Nucleic acids research
Auteurs
Membres identifiés du Cancéropôle Est :
Pr IMLER Jean-Luc
,
Dr MEIGNIN Carine
Tous les auteurs :
Gross L, Vicens Q, Einhorn E, Noireterre A, Schaeffer L, Kuhn L, Imler JL, Eriani G, Meignin C, Martin F
Lien Pubmed
Résumé
Cricket paralysis virus (CrPV) is a dicistrovirus. Its positive-sense single-stranded RNA genome contains two internal ribosomal entry sites (IRESs). The 5' untranslated region (5'UTR) IRES5'UTR mediates translation of non-structural proteins encoded by ORF1 whereas the well-known intergenic region (IGR) IRESIGR is required for translation of structural proteins from open reading frame 2 in the late phase of infection. Concerted action of both IRES is essential for host translation shut-off and viral translation. IRESIGR has been extensively studied, in contrast the IRES5'UTR remains largely unexplored. Here, we define the minimal IRES element required for efficient translation initiation in drosophila S2 cell-free extracts. We show that IRES5'UTR promotes direct recruitment of the ribosome on the cognate viral AUG start codon without any scanning step, using a Hepatitis-C virus-related translation initiation mechanism. Mass spectrometry analysis revealed that IRES5'UTR recruits eukaryotic initiation factor 3, confirming that it belongs to type III class of IRES elements. Using Selective 2'-hydroxyl acylation analyzed by primer extension and DMS probing, we established a secondary structure model of 5'UTR and of the minimal IRES5'UTR. The IRES5'UTR contains a pseudoknot structure that is essential for proper folding and ribosome recruitment. Overall, our results pave the way for studies addressing the synergy and interplay between the two IRES from CrPV.
Mots clés
5' Untranslated Regions, Animals, Base Sequence, Cell Line, Cell-Free System, metabolism, Dicistroviridae, genetics, Drosophila melanogaster, virology, Gryllidae, virology, Host-Pathogen Interactions, Internal Ribosome Entry Sites, Nucleic Acid Conformation, Open Reading Frames, Protein Biosynthesis, RNA, Viral, chemistry, Ribosomes, genetics, Viral Proteins, chemistry
Référence
Nucleic Acids Res.. 2017 Sep 6;45(15):8993-9004
