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. 1996 Dec;16(12):6859–6869. doi: 10.1128/mcb.16.12.6859

Canonical eukaryotic initiation factors determine initiation of translation by internal ribosomal entry.

T V Pestova 1, C U Hellen 1, I N Shatsky 1
PMCID: PMC231689  PMID: 8943341

Abstract

Translation of picornavirus RNA is initiated after ribosomal binding to an internal ribosomal entry site (IRES) within the 5' untranslated region. We have reconstituted IRES-mediated initiation on encephalomyocarditis virus RNA from purified components and used primer extension analysis to confirm the fidelity of 48S preinitiation complex formation. Eukaryotic initiation factor 2 (eIF2), eIF3, and eIF4F were required for initiation; eIF4B and to a lesser extent the pyrimidine tract-binding protein stimulated this process. We show that eIF4F binds to the IRES in a novel cap-independent manner and suggest that cap- and IRES-dependent initiation mechanisms utilize different modes of interaction with this factor to promote ribosomal attachment to mRNA.

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Selected References

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