title: Multiple mechanisms of reinitiation on bicistronic calicivirus mRNAs.
abstract: Reinitiation is a strategy used by viruses to express several cistrons from one mRNA. Although extremely weak after translation of long open reading frames (ORFs) on cellular mRNAs, reinitiation occurs efficiently on subgenomic bicistronic calicivirus mRNAs, enabling synthesis of minor capsid proteins. The process is governed by a short element upstream of the restart AUG, designated "termination upstream ribosomal binding site" (TURBS). It contains the conserved Motif 1 complementary to h26 of 18S rRNA, displayed in the loop of a hairpin formed by species-specific Motifs 2/2(∗). To determine the advantages conferred on reinitiation by TURBS, we reconstituted this process in vitro on two model bicistronic calicivirus mRNAs. We found that post-termination ribosomal tethering of mRNA by TURBS allows reinitiation by post-termination 80S ribosomes and diminishes dependence on eukaryotic initiation factor 3 (eIF3) of reinitiation by recycled 40S subunits, which can be mediated either by eIFs 2/1/1A or by Ligatin following ABCE1-dependent or -independent splitting of post-termination complexes.
authors: Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
authors: Alexandra
authors: A
authors: Zinoviev
authors: Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA.
authors: Christopher U T
authors: CUT
authors: Hellen
authors: Department of Cell Biology, SUNY Downstate Medical Center, 450 Clarkson Avenue, Brooklyn, NY 11203, USA. Electronic address: tatyana.pestova@downstate.edu.
authors: Tatyana V
authors: TV
authors: Pestova
mesh_terms: D001483:Base Sequence; D001665:Binding Sites; D003062:Codon; D015977:Eukaryotic Initiation Factor-1 / Q000235:genetics / Q000378:metabolism; D015852:Eukaryotic Initiation Factor-2 / Q000235:genetics / Q000378:metabolism; D039621:Eukaryotic Initiation Factor-3 / Q000235:genetics / Q000378:metabolism; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D017929:Hemorrhagic Disease Virus, Rabbit / Q000235:genetics* / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D029322:Norovirus / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D054682:Ribosome Subunits, Small, Eukaryotic / Q000235:genetics / Q000378:metabolism; D012270:Ribosomes / Q000235:genetics / Q000378:metabolism
chemical_list: D003062:Codon; D015977:Eukaryotic Initiation Factor-1; D015852:Eukaryotic Initiation Factor-2; D039621:Eukaryotic Initiation Factor-3; D008565:Membrane Proteins; D012333:RNA, Messenger; C026022:eukaryotic peptide initiation factor-1A; C013090:ligatin