The RNA recognition motif of eukaryotic translation initiation factor 3g (eIF3g) is required for resumption of scanning of posttermination ribosomes for reinitiation on GCN4 and together with eIF3i stimulates linear scanning
Jazyk angličtina Země Spojené státy americké Médium print-electronic
Typ dokumentu časopisecké články, práce podpořená grantem
Grantová podpora
076456
Wellcome Trust - United Kingdom
Howard Hughes Medical Institute - United States
076456/Z/05/Z
Wellcome Trust - United Kingdom
PubMed
20679478
PubMed Central
PMC2950517
DOI
10.1128/mcb.00430-10
PII: MCB.00430-10
Knihovny.cz E-zdroje
- MeSH
- aminokyselinové motivy genetika MeSH
- eukaryotický iniciační faktor 3 chemie genetika metabolismus MeSH
- fungální RNA metabolismus MeSH
- messenger RNA genetika metabolismus MeSH
- molekulární modely MeSH
- molekulární sekvence - údaje MeSH
- mutace MeSH
- podjednotky proteinů chemie genetika metabolismus MeSH
- proteosyntéza * MeSH
- ribozomální proteiny chemie genetika metabolismus MeSH
- ribozomy genetika metabolismus MeSH
- Saccharomyces cerevisiae - proteiny chemie genetika metabolismus MeSH
- Saccharomyces cerevisiae genetika metabolismus MeSH
- sekundární struktura proteinů MeSH
- sekvence aminokyselin MeSH
- sekvenční homologie aminokyselin MeSH
- substituce aminokyselin MeSH
- terciární struktura proteinů MeSH
- transkripční faktory bZIP genetika metabolismus MeSH
- vazba proteinů MeSH
- western blotting MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- eukaryotický iniciační faktor 3 MeSH
- fungální RNA MeSH
- GCN4 protein, S cerevisiae MeSH Prohlížeč
- messenger RNA MeSH
- podjednotky proteinů MeSH
- ribozomální proteiny MeSH
- RPS20 protein, S cerevisiae MeSH Prohlížeč
- RPS3 protein, S cerevisiae MeSH Prohlížeč
- Saccharomyces cerevisiae - proteiny MeSH
- transkripční faktory bZIP MeSH
Recent reports have begun unraveling the details of various roles of individual eukaryotic translation initiation factor 3 (eIF3) subunits in translation initiation. Here we describe functional characterization of two essential Saccharomyces cerevisiae eIF3 subunits, g/Tif35 and i/Tif34, previously suggested to be dispensable for formation of the 48S preinitiation complexes (PICs) in vitro. A triple-Ala substitution of conserved residues in the RRM of g/Tif35 (g/tif35-KLF) or a single-point mutation in the WD40 repeat 6 of i/Tif34 (i/tif34-Q258R) produces severe growth defects and decreases the rate of translation initiation in vivo without affecting the integrity of eIF3 and formation of the 43S PICs in vivo. Both mutations also diminish induction of GCN4 expression, which occurs upon starvation via reinitiation. Whereas g/tif35-KLF impedes resumption of scanning for downstream reinitiation by 40S ribosomes terminating at upstream open reading frame 1 (uORF1) in the GCN4 mRNA leader, i/tif34-Q258R prevents full GCN4 derepression by impairing the rate of scanning of posttermination 40S ribosomes moving downstream from uORF1. In addition, g/tif35-KLF reduces processivity of scanning through stable secondary structures, and g/Tif35 specifically interacts with Rps3 and Rps20 located near the ribosomal mRNA entry channel. Together these results implicate g/Tif35 and i/Tif34 in stimulation of linear scanning and, specifically in the case of g/Tif35, also in proper regulation of the GCN4 reinitiation mechanism.
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Please do not recycle! Translation reinitiation in microbes and higher eukaryotes
Translation initiation factor eIF3 promotes programmed stop codon readthrough
