Eukaryotic ribosomes require initiation factors 1 and 1A to locate initiation codons

Tatyana V. Pestova, Sergei I. Borukhov, Christopher U.T. Hellen

Research output: Contribution to journalArticlepeer-review

295 Scopus citations


The scanning model of translation initiation is a coherent description of how eukaryotic ribosomes reach the initiation codon after being recruited to the capped 5' end of messenger RNA. Five eukaryotic initiation factors (eIF 2, 3, 4A, 4B and 4F) with established functions have been assumed to be sufficient to mediate this process. Here we report that eIF1 and eIF1A are also both essential for translation initiation. In their absence, 43S ribosomal preinitiation complexes incubated with ATP, eIF4A, eIF4B and eIF4F bind exclusively to the cap-proximal region but are unable to reach the initiation codon. Individually, eIF1A enhances formation of this cap-proximal complex, and eIF1 weakly promotes formation of a 48S ribosomal complex at the initiation codon. These proteins act synergistically to mediate assembly of ribosomal initiation complexes at the initiation codon and dissociate aberrant complexes from the mRNA.

Original languageEnglish (US)
Pages (from-to)854-859
Number of pages6
Issue number6696
StatePublished - Aug 27 1998

All Science Journal Classification (ASJC) codes

  • General

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