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Translation of 5' leaders is pervasive in genes resistant to eIF2 repression.

Andreev DE, O'Connor PB, Fahey C, Kenny EM, Terenin IM, Dmitriev SE, Cormican P, Morris DW, Shatsky IN, Baranov PV - Elife (2015)

Bottom Line: However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response.Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition.Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products.

View Article: PubMed Central - PubMed

Affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.

ABSTRACT
Eukaryotic cells rapidly reduce protein synthesis in response to various stress conditions. This can be achieved by the phosphorylation-mediated inactivation of a key translation initiation factor, eukaryotic initiation factor 2 (eIF2). However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response. We carried out ribosome profiling of cultured human cells under conditions of severe stress induced with sodium arsenite. Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition. Nearly all resistant transcripts possess at least one efficiently translated upstream open reading frame (uORF) that represses translation of the main coding ORF under normal conditions. Site-specific mutagenesis of two identified stress resistant mRNAs (PPP1R15B and IFRD1) demonstrated that a single uORF is sufficient for eIF2-mediated translation control in both cases. Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products.

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(A) Effect mutations that improve initiation Kozakcontext for uAUG in the IFRD1 leader during arsenite treatment.(B) Effect of Torin-1 treatment on translation of differentreporter mRNAs in HEK293T.DOI:http://dx.doi.org/10.7554/eLife.03971.017
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fig4s3: (A) Effect mutations that improve initiation Kozakcontext for uAUG in the IFRD1 leader during arsenite treatment.(B) Effect of Torin-1 treatment on translation of differentreporter mRNAs in HEK293T.DOI:http://dx.doi.org/10.7554/eLife.03971.017

Mentions: Treatment with a potent inhibitor of mTOR kinase, torin-1 (Thoreen et al., 2009), led to inhibited translation of thesereporters to the same degree as the control pGL3 mRNA (Figure 4—figure supplement 3). Thus,IFRD1 or PPP1R15B leaders do not providetranslational resistance to the stress response that involves sequestration of thecap-binding protein eIF4E.


Translation of 5' leaders is pervasive in genes resistant to eIF2 repression.

Andreev DE, O'Connor PB, Fahey C, Kenny EM, Terenin IM, Dmitriev SE, Cormican P, Morris DW, Shatsky IN, Baranov PV - Elife (2015)

(A) Effect mutations that improve initiation Kozakcontext for uAUG in the IFRD1 leader during arsenite treatment.(B) Effect of Torin-1 treatment on translation of differentreporter mRNAs in HEK293T.DOI:http://dx.doi.org/10.7554/eLife.03971.017
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4383229&req=5

fig4s3: (A) Effect mutations that improve initiation Kozakcontext for uAUG in the IFRD1 leader during arsenite treatment.(B) Effect of Torin-1 treatment on translation of differentreporter mRNAs in HEK293T.DOI:http://dx.doi.org/10.7554/eLife.03971.017
Mentions: Treatment with a potent inhibitor of mTOR kinase, torin-1 (Thoreen et al., 2009), led to inhibited translation of thesereporters to the same degree as the control pGL3 mRNA (Figure 4—figure supplement 3). Thus,IFRD1 or PPP1R15B leaders do not providetranslational resistance to the stress response that involves sequestration of thecap-binding protein eIF4E.

Bottom Line: However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response.Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition.Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products.

View Article: PubMed Central - PubMed

Affiliation: Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.

ABSTRACT
Eukaryotic cells rapidly reduce protein synthesis in response to various stress conditions. This can be achieved by the phosphorylation-mediated inactivation of a key translation initiation factor, eukaryotic initiation factor 2 (eIF2). However, the persistent translation of certain mRNAs is required for deployment of an adequate stress response. We carried out ribosome profiling of cultured human cells under conditions of severe stress induced with sodium arsenite. Although this led to a 5.4-fold general translational repression, the protein coding open reading frames (ORFs) of certain individual mRNAs exhibited resistance to the inhibition. Nearly all resistant transcripts possess at least one efficiently translated upstream open reading frame (uORF) that represses translation of the main coding ORF under normal conditions. Site-specific mutagenesis of two identified stress resistant mRNAs (PPP1R15B and IFRD1) demonstrated that a single uORF is sufficient for eIF2-mediated translation control in both cases. Phylogenetic analysis suggests that at least two regulatory uORFs (namely, in SLC35A4 and MIEF1) encode functional protein products.

Show MeSH
Related in: MedlinePlus