Cap-independent translation by DAP5 controls cell fate decisions in human embryonic stem cells
- Yael Yoffe1,
- Maya David1,
- Rinat Kalaora1,
- Lital Povodovski1,
- Gilgi Friedlander2,
- Ester Feldmesser3,
- Elena Ainbinder4,
- Ann Saada5,6,
- Shani Bialik1 and
- Adi Kimchi1
- 1Department of Molecular Genetics, Weizmann Institute of Science, Rehovot 76100, Israel;
- 2Nancy and Stephen Grand Israel National Center for Personalized Medicine, Weizmann Institute of Science, Rehovot 76100, Israel;
- 3Bioinformatics Unit, Weizmann Institute of Science, Rehovot 76100, Israel;
- 4Stem Cell Core Unit, Weizmann Institute of Science, Rehovot 76100, Israel;
- 5Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel;
- 6Department of Genetics and Metabolic Diseases, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
- Corresponding author: adi.kimchi{at}weizmann.ac.il
Abstract
Multiple transcriptional and epigenetic changes drive differentiation of embryonic stem cells (ESCs). This study unveils an additional level of gene expression regulation involving noncanonical, cap-independent translation of a select group of mRNAs. This is driven by death-associated protein 5 (DAP5/eIF4G2/NAT1), a translation initiation factor mediating IRES-dependent translation. We found that the DAP5 knockdown from human ESCs (hESCs) resulted in persistence of pluripotent gene expression, delayed induction of differentiation-associated genes in different cell lineages, and defective embryoid body formation. The latter involved improper cellular organization, lack of cavitation, and enhanced mislocalized apoptosis. RNA sequencing of polysome-associated mRNAs identified candidates with reduced translation efficiency in DAP5-depleted hESCs. These were enriched in mitochondrial proteins involved in oxidative respiration, a pathway essential for differentiation, the significance of which was confirmed by the aberrant mitochondrial morphology and decreased oxidative respiratory activity in DAP5 knockdown cells. Further analysis identified the chromatin modifier HMGN3 as a cap-independent DAP5 translation target whose knockdown resulted in defective differentiation. Thus, DAP5-mediated translation of a specific set of proteins is critical for the transition from pluripotency to differentiation, highlighting the importance of cap-independent translation in stem cell fate decisions.
Keywords
- DAP5
- cap-independent translation
- human embryonic stem cells
- stem cell differentiation
- protein translation control
Footnotes
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Supplemental material is available for this article.
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Article is online at http://www.genesdev.org/cgi/doi/10.1101/gad.285239.116.
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Freely available online through the Genes & Development Open Access option.
- Received June 9, 2016.
- Accepted August 18, 2016.
This article, published in Genes & Development, is available under a Creative Commons License (Attribution-NonCommercial 4.0 International), as described at http://creativecommons.org/licenses/by-nc/4.0/.