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EIF4A1 is essential in B cells by promoting activation-induced translation

ABSTRACT: EIF4A1 and cofactors EIF4B and EIF4H have been well characterised in cancers, including B cell malignancies, for their ability to promote the translation of oncogenes with structured 5’ untranslated regions but very little is known of their roles in non-malignant cells. Using mouse models to delete Eif4a1, Eif4b or Eif4h in B cells we show that EIF4A1, but not EIF4B or EIF4H, is essential for B cell development and the germinal centre response. Following activation, EIF4A1 facilitates an increased rate of protein synthesis, MYC expression and expression of cell cycle regulators. However, EIF4A1-deficient cells remain viable whereas Hippuristanol treatment induces cell death.

ORGANISM(S): Mus musculus

PROVIDER: GSE237426 | GEO | 2023/07/21

REPOSITORIES: GEO

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RNA helicase EIF4A1-mediated translation is essential for the GC response

Project description:EIF4A1 and cofactors EIF4B and EIF4H have been well characterised in cancers, including B cell malignancies, for their ability to promote the translation of oncogenes with structured 5’ untranslated regions. However, very little is known of their roles in non-malignant cells. Using mouse models to delete Eif4a1, Eif4b or Eif4h in B cells we show that EIF4A1, but not EIF4B or EIF4H, is essential for B cell development and the germinal centre response. Following B cell activation in vitro, EIF4A1 facilitates an increased rate of protein synthesis, MYC expression and expression of cell cycle regulators. However, EIF4A1-deficient cells remain viable whereas inhibition of EIF4A1 and EIF4A2 by Hippuristanol treatment induces cell death.

2023-11-09 | PXD046710 | Pride

eIF4A1 unwinding activity is RNA sequence-specifically deployed through eIF4A1-multimerisation to facilitate translation of mRNAs with local repressive RNA structure

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2023-01-17 | PXD034343 | Pride

eIF4A1 enhances LARP1-mediated translational repression during mTORC1 inhibition

Project description:Eukaryotic translation initiation factor (eIF) 4A — a DEAD-box RNA-binding protein — plays an essential role in translation initiation. Recent reports have suggested helicase-dependent and helicase-independent functions for eIF4A, but the multifaceted roles of eIF4A have not been fully explored. Here, we show that eIF4A1 enhances translational repression during the inhibition of mechanistic target of rapamycin complex 1 (mTORC1), an essential kinase complex controlling cell proliferation. RNA pulldown followed by sequencing revealed that eIF4A1 preferentially binds to mRNAs containing terminal oligopyrimidine (TOP) motifs (TOP mRNAs), whose translation is rapidly repressed upon mTORC1 inhibition. This selective interaction depends on a La-related RNA-binding protein, LARP1. Ribosome profiling revealed that deletion of EIF4A1 attenuated the translational repression of TOP mRNAs upon mTORC1 inactivation. Moreover, eIF4A1 increases the affinity between TOP mRNAs and LARP1 and thus ensures stronger translational repression upon mTORC1 inhibition. Our data show the multimodality of eIF4A1 in modulating protein synthesis through an inhibitory binding partner and provide a unique example of the repressive role of a universal translational activator.

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Authentication of Hippuristanol-eIF4A1 Target Engagement Facilitates Identification of eIF4A1 Helicase Dependencies within 5’ Leader Regions

Project description:Hippuristanol (Hipp) is a natural product that selectively inhibits protein synthesis by targeting eukaryotic initiation factor (eIF) 4A, a DEAD-box RNA helicase required for ribosome recruitmentt o mRNA templates. Using a CRISPR/Cas9-based variomics screen, we identify functional eIF4A1 Hipp-resistant alleles, which in turn allow us to link the translation-inhibitory and cytotoxic properties of Hipp to eIF4A1 target-engagement. Genome-wide translational profiling in the absence or presence of Hipp (~EC50) were undertaken and our validation studies provided insight into structure-activity relationships of eIF4A-dependent mRNAs.

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Genome-wide analysis of transcriptome and translatome following eIF4A1 knockdown in MCF7 cells [Array]

Project description:To identify which genes were regulated by mRNA helicase activity, the effect of eIF4A1 knockdown on the MCF7 cell transcriptome and translatome was determined. eIF4A1-dependent mRNAs were highly enriched for several classes of genes with oncogenic potential, which leads to a model whereby dysregulation of mRNA unwinding contribues to the malignant phenotype in breast cancer cells via preferential translation of a subset of genes.

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Genome-wide analysis of transcriptome and translatome following eIF4A1 knockdown in MCF7 cells [RNA-Seq]

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eIF4B preferentially stimulates translation of long mRNAs with structured 5’UTRs and low closed-loop potential but weak dependence on eIF4G

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2016-05-27 | GSE81966 | GEO

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Authentication of Hippuristanol-eIF4A1 Target Engagement Facilitates Identification of eIF4A1 Helicase Dependencies within 5’ Leader Regions

Project description:Authentication of Hippuristanol-eIF4A1 Target Engagement Facilitates Identification of eIF4A1 Helicase Dependencies within 5’ Leader Regions

| PRJNA636959 | ENA

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