title: Structural and functional diversity of viral IRESes.
abstract: Some 20 years ago, the study of picornaviral RNA translation led to the characterization of an alternative mechanism of initiation by direct ribosome binding to the 5' UTR. By using a bicistronic vector, it was shown that the 5' UTR of the poliovirus (PV) or the Encephalomyelitis virus (EMCV) had the ability to bind the 43S preinitiation complex in a 5' and cap-independent manner. This is rendered possible by an RNA domain called IRES for Internal Ribosome Entry Site which enables efficient translation of an mRNA lacking a 5' cap structure. IRES elements have now been found in many different viral families where they often confer a selective advantage to allow ribosome recruitment under conditions where cap-dependent protein synthesis is severely repressed. In this review, we compare and contrast the structure and function of IRESes that are found within 4 distinct family of RNA positive stranded viruses which are the (i) Picornaviruses; (ii) Flaviviruses; (iii) Dicistroviruses; and (iv) Lentiviruses.
authors.affiliation: Unité de Virologie Humaine, Ecole Normale Supérieure de Lyon, Lyon F-693643, France.
authors.forename: Laurent
authors.initials: L
authors.lastname: Balvay
authors.forename: Ricardo
authors.initials: R
authors.lastname: Soto Rifo
authors.forename: Emiliano P
authors.initials: EP
authors.lastname: Ricci
authors.forename: Didier
authors.initials: D
authors.lastname: Decimo
authors.forename: Théophile
authors.initials: T
authors.lastname: Ohlmann
mesh_terms: D020121:5' Untranslated Regions; D003062:Codon; D004679:Encephalomyelitis / Q000821:virology; D005796:Genes; D015498:HIV-2 / Q000235:genetics; D006801:Humans; D008957:Models, Genetic; D009690:Nucleic Acid Conformation; D016366:Open Reading Frames; D010849:Picornaviridae / Q000235:genetics*; D017955:Poliovirus / Q000235:genetics; D011061:Poly A; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D012367:RNA, Viral; D012270:Ribosomes / Q000378:metabolism; D015533:Transcriptional Activation; D014779:Virus Replication
chemical_list: D020121:5' Untranslated Regions; D003062:Codon; D012333:RNA, Messenger; D012367:RNA, Viral; D011061:Poly A