Ania Wilczynska, Sarah L Gillen, Tobias Schmidt, Hedda A Meijer, Rebekah Jukes-Jones, Claudia Langlais, Kari Kopra, Wei-Ting Lu, Jack D Godfrey, Benjamin R Hawley, Kelly Hodge, Sara Zanivan, Kelvin Cain, John Le Quesne, Martin Bushell
Genome biology 2019 Dec 02Regulation 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. 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. 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.
Ania Wilczynska, Sarah L Gillen, Tobias Schmidt, Hedda A Meijer, Rebekah Jukes-Jones, Claudia Langlais, Kari Kopra, Wei-Ting Lu, Jack D Godfrey, Benjamin R Hawley, Kelly Hodge, Sara Zanivan, Kelvin Cain, John Le Quesne, Martin Bushell. eIF4A2 drives repression of translation at initiation by Ccr4-Not through purine-rich motifs in the 5'UTR. Genome biology. 2019 Dec 02;20(1):262
PMID: 31791371
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