Global mRNA Stabilization Preferentially Linked to Translational Repression during the Endoplasmic Reticulum Stress Response

Abstract

The stability of mRNAs undergoing translation has long been a controversial question. Here, we systematically investigate links between mRNA turnover and translation during the endoplasmic reticulum (ER) stress response, a process during which protein synthesis is potently regulated. cDNA array-based approaches to assess the stability and translational status of each mRNA were devised. First, ER stress-triggered changes in mRNA stability were studied by comparing differences in steady-state mRNA levels with differences in gene transcription. Second, changes in translational status were monitored by studying ER stress-induced shifts in the relative distribution of each mRNA along sucrose gradients. Together, the array-derived data reveal complex links between mRNA stability and translation, with all regulatory groups represented: both stabilized and destabilized mRNAs were found among translationally induced as well as translationally suppressed mRNA collections. Remarkably, however, the subset of stabilized mRNAs was prominently enriched in translationally suppressed transcripts, suggesting that ER stress was capable of causing the stabilization of mRNAs associated with a global reduction in protein synthesis. The cDNA array-based approach described here can be applied to global analyses of mRNA turnover and translation and can serve to investigate subsets of mRNAs subject to joint posttranscriptional control.

Translational Control of Cytochrome c by RNA-Binding Proteins TIA-1 and HuR

“…Our previous studies had uncovered global links between mRNA stabilization and translational control during ER stress (22). We obtained systematic evidence that altered mRNA turnover strongly influenced changes in steady-state mRNA levels during the ER stress response and that translation was widely repressed.…”

“…For Western blot analysis, whole-cell (10 g), cytoplasmic (20 g), and nuclear (10 g) lysates were prepared (22), size fractionated by electrophoresis through Tris-HCl gels (Bio-Rad, Life Science), and transferred onto polyvinylidene difluoride membranes. Monoclonal antibodies recognizing HuR and ␣-tubulin (a control cytoplasmic protein) as well as goat polyclonal anti-TIA-1 and anti-TIAR antibodies and a rabbit polyclonal antibody recognizing hnRNP C1/C2 (a control nuclear protein) were from Santa Cruz Biotechnology.…”

“…We obtained systematic evidence that altered mRNA turnover strongly influenced changes in steady-state mRNA levels during the ER stress response and that translation was widely repressed. When the collections of mRNAs present in each turnover and translation group were further contrasted, the most prominently represented group comprised mRNAs that were subject to translational repression and were preferentially stabilized by ER stress (22). To further investigate these observations, we have studied a specific mRNA present in this group, that encoding cytochrome c. We have identified TIA-1 and HuR as RBPs forming specific RNP complexes with the cytochrome c mRNA, have obtained evidence that they potently influence cytochrome c translation, and document the functional consequences of these RNP associations following ER stress.…”

Unfolded Protein Response Is Required for the Definitive Endodermal Specification of Mouse Embryonic Stem Cells via Smad2 and β-Catenin Signaling

“…Recent findings indicate that ER stress might alter gene expression beyond protein folding (34). The ER stress inducers TG and TM are able to enhance the expression of differentiation genes in addition to genes encoding secretory polypeptides, membrane proteins, and growth factors (18 -20).…”

“…stress can active a number of signaling pathways (22,33,34). Previous studies reported that the TGF-␤/Smad, Wnt/␤-catenin, and FGF signaling pathways can regulate the formation of the definitive endoderm (2,4,7).…”