title: The mechanism of translation initiation on Aichivirus RNA mediated by a novel type of picornavirus IRES.
abstract: Picornavirus mRNAs contain IRESs that sustain their translation during infection, when host protein synthesis is shut off. The major classes of picornavirus IRESs (Types 1 and 2) have distinct structures and sequences, but initiation on both is determined by their specific interaction with eIF4G. We report here that Aichivirus (AV), a member of the Kobuvirus genus of Picornaviridae, contains an IRES that differs structurally from Type 1 and Type 2 IRESs. Its function similarly involves interaction with eIF4G, but its eIF4G-interacting domain is structurally distinct, although it contains an apical eIF4G-interacting motif similar to that in Type 2 IRESs. Like Type 1 and Type 2 IRESs, AV IRES function is enhanced by pyrimidine tract-binding protein (PTB), but the pattern of PTB's interaction with each of these IRESs is distinct. Unlike all known IRESs, the AV IRES is absolutely dependent on DHX29, a requirement imposed by sequestration of its initiation codon in a stable hairpin.
authors.affiliation: Department of Cell Biology, SUNY Downstate Medical Center, Brooklyn, NY, USA.
authors.forename: Yingpu
authors.initials: Y
authors.lastname: Yu
authors.forename: Trevor R
authors.initials: TR
authors.lastname: Sweeney
authors.forename: Panagiota
authors.initials: P
authors.lastname: Kafasla
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Jackson
authors.forename: Tatyana V
authors.initials: TV
authors.lastname: Pestova
authors.forename: Christopher Ut
authors.initials: CU
authors.lastname: Hellen
mesh_terms: D020121:5' Untranslated Regions / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites / Q000235:genetics; D015967:Gene Expression Regulation, Viral; D052699:Kobuvirus / Q000235:genetics*; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D010442:Peptide Chain Initiation, Translational / Q000235:genetics*; D010849:Picornaviridae / Q000235:genetics* / Q000378:metabolism; D014176:Protein Biosynthesis / Q000235:genetics / Q000502:physiology; D012367:RNA, Viral / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D050436:Regulatory Elements, Transcriptional / Q000235:genetics / Q000502:physiology*; D012270:Ribosomes / Q000378:metabolism
chemical_list: D020121:5' Untranslated Regions; D012367:RNA, Viral