» Articles » PMID: 16467844

Gene Expression During Acute and Prolonged Hypoxia is Regulated by Distinct Mechanisms of Translational Control

Abstract

Hypoxia has recently been shown to activate the endoplasmic reticulum kinase PERK, leading to phosphorylation of eIF2alpha and inhibition of mRNA translation initiation. Using a quantitative assay, we show that this inhibition exhibits a biphasic response mediated through two distinct pathways. The first occurs rapidly, reaching a maximum at 1-2 h and is due to phosphorylation of eIF2alpha. Continued hypoxic exposure activates a second, eIF2alpha-independent pathway that maintains repression of translation. This phase is characterized by disruption of eIF4F and sequestration of eIF4E by its inhibitor 4E-BP1 and transporter 4E-T. Quantitative RT-PCR analysis of polysomal RNA indicates that the translation efficiency of individual genes varies widely during hypoxia. Furthermore, the translation efficiency of individual genes is dynamic, changing dramatically during hypoxic exposure due to the initial phosphorylation and subsequent dephosphorylation of eIF2alpha. Together, our data indicate that acute and prolonged hypoxia regulates mRNA translation through distinct mechanisms, each with important contributions to hypoxic gene expression.

Citing Articles

Cardiomyocytes in Hypoxia: Cellular Responses and Implications for Cell-Based Cardiac Regenerative Therapies.

Dwyer K, Snyder C, Coulombe K Bioengineering (Basel). 2025; 12(2).

PMID: 40001674 PMC: 11851968. DOI: 10.3390/bioengineering12020154.


Adaptation of Natural Killer Cells to Hypoxia: A Review of the Transcriptional, Translational, and Metabolic Processes.

Chang T, Chen Y, Luo J, Zhang C, Chen S, Lin Z Immunotargets Ther. 2025; 14:99-121.

PMID: 39990274 PMC: 11846490. DOI: 10.2147/ITT.S492334.


Tumour hypoxia in driving genomic instability and tumour evolution.

Suvac A, Ashton J, Bristow R Nat Rev Cancer. 2025; 25(3):167-188.

PMID: 39875616 DOI: 10.1038/s41568-024-00781-9.


Glucose deprivation impairs hypoxia-inducible factor-1α synthesis.

Hubert M, Stuart S, Ohh M Discov Oncol. 2024; 15(1):595.

PMID: 39466364 PMC: 11519269. DOI: 10.1007/s12672-024-01484-1.


Ribosome biogenesis and ribosomal proteins in cancer stem cells: a new therapeutic prospect.

Samanta P, Ghosh R, Pakhira S, Mondal M, Biswas S, Sarkar R Mol Biol Rep. 2024; 51(1):1016.

PMID: 39325314 DOI: 10.1007/s11033-024-09963-y.


References
1.
Holland E, Sonenberg N, Pandolfi P, Thomas G . Signaling control of mRNA translation in cancer pathogenesis. Oncogene. 2004; 23(18):3138-44. DOI: 10.1038/sj.onc.1207590. View

2.
Andrei M, Ingelfinger D, Heintzmann R, Achsel T, Rivera-Pomar R, Luhrmann R . A role for eIF4E and eIF4E-transporter in targeting mRNPs to mammalian processing bodies. RNA. 2005; 11(5):717-27. PMC: 1370757. DOI: 10.1261/rna.2340405. View

3.
Blais J, Filipenko V, Bi M, Harding H, Ron D, Koumenis C . Activating transcription factor 4 is translationally regulated by hypoxic stress. Mol Cell Biol. 2004; 24(17):7469-82. PMC: 506979. DOI: 10.1128/MCB.24.17.7469-7482.2004. View

4.
Romero-Ramirez L, Cao H, Nelson D, Hammond E, Lee A, Yoshida H . XBP1 is essential for survival under hypoxic conditions and is required for tumor growth. Cancer Res. 2004; 64(17):5943-7. DOI: 10.1158/0008-5472.CAN-04-1606. View

5.
Cardenas-Navia L, Yu D, Braun R, Brizel D, Secomb T, Dewhirst M . Tumor-dependent kinetics of partial pressure of oxygen fluctuations during air and oxygen breathing. Cancer Res. 2004; 64(17):6010-7. DOI: 10.1158/0008-5472.CAN-03-0947. View