eIF4A2 drives repression of translation at initiation by Ccr4-Not through purine-rich motifs in the 5’UTR (original) (raw)

Wilczynska, A. et al. (2019) eIF4A2 drives repression of translation at initiation by Ccr4-Not through purine-rich motifs in the 5’UTR.Genome Biology, 20, 262. (doi: 10.1186/s13059-019-1857-2) (PMID:31791371) (PMCID:PMC6886185)

Abstract

Background: Regulation of the mRNA life cycle is central to gene expression control and determination of cell fate. miRNAs represent a critical mRNA regulatory mechanism, but despite decades of research, their mode of action is still not fully understood. Results: Here, we show that eIF4A2 is a major effector of the repressive miRNA pathway functioning via the Ccr4-Not complex. We demonstrate that while DDX6 interacts with Ccr4-Not, its effects in the mechanism are not as pronounced. Through its interaction with the Ccr4-Not complex, eIF4A2 represses mRNAs at translation initiation. We show evidence that native eIF4A2 has similar RNA selectivity to chemically inhibited eIF4A1. eIF4A2 exerts its repressive effect by binding purine-rich motifs which are enriched in the 5′UTR of target mRNAs directly upstream of the AUG start codon. Conclusions: Our data support a model whereby purine motifs towards the 3′ end of the 5′UTR are associated with increased ribosome occupancy and possible uORF activation upon eIF4A2 binding.

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Funder and Project Information

Mechanistic determination of how microRNAs control gene-expression

Martin Bushell

BB/N017005/2

CS - Beatson Institute for Cancer Research

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