Project description:To examine the relationship between protein synthesis and energy homeostasis, we created the whole body eIF2α haploinsufficient mouse model to establish a constantly reduced translation state.
Project description:Previously we observed that when constantly reducing protein synthesis using the whole-body eIF2α haploinsufficient mouse model, the hepatic lipogenesis process would gear down. To figure out whether translation can regulate lipogenesis in a cell-autonomous way, we created the liver-specific eIF4EBP3 deficient mouse by adenovirus-mediated shRNA targeting Eif4ebp3. eIF4EBP3 suppresses translation initiation by sequestering eIF4E. Therefore, by knocking down it, we established a translation hyperactive state in liver.
Project description:The integrated stress response (ISR) is critical for cell survival under stress. In response to diverse environmental cues, eIF2αbecomes phosphorylated, engendering a dramatic change in mRNA translation. The activation of ISR plays a pivotal role in the early embryogenesis but the eIF2-dependent translational landscape in pluripotent embryonic stem cells (ESC) is largely unexplored. We employ a multi-omics approachconsisting of ribosome profiling, proteomics, and metabolomics inwild-type(eIF2α+/+)andphosphorylation-deficient mutant eIF2α(eIF2αA/A)mouse ESCs (mESCs) to investigate phosphorylated (p)-eIF2α-dependent translational control of naïve pluripotency. We show a transient increase in p-eIF2α in the naïve epiblast layer of E4.5 embryos. Absence of eIF2α phosphorylation engenders an exit from naive pluripotency following 2i (two chemical inhibitors of MEK1/2 and GSK3α/β) withdrawal. p-eIF2α controls translation of mRNAs encoding proteins which govern pluripotency, chromatin organization, and glutathione synthesis.Thus, p-eIF2αacts as a key regulator of the naïve pluripotency gene regulatory network.
Project description:The integrated stress response (ISR) is critical for cell survival under stress. In response to diverse environmental cues, eIF2αbecomes phosphorylated, engendering a dramatic change in mRNA translation. The activation of ISR plays a pivotal role in the early embryogenesis but the eIF2-dependent translational landscape in pluripotent embryonic stem cells (ESC) is largely unexplored. We employ a multi-omics approachconsisting of ribosome profiling, proteomics, and metabolomics inwild-type(eIF2α+/+)andphosphorylation-deficient mutant eIF2α(eIF2αA/A)mouse ESCs (mESCs) to investigate phosphorylated (p)-eIF2α-dependent translational control of naïve pluripotency. We show a transient increase in p-eIF2α in the naïve epiblast layer of E4.5 embryos. Absence of eIF2α phosphorylation engenders an exit from naive pluripotency following 2i (two chemical inhibitors of MEK1/2 and GSK3α/β) withdrawal. p-eIF2α controls translation of mRNAs encoding proteins which govern pluripotency, chromatin organization, and glutathione synthesis.Thus, p-eIF2αacts as a key regulator of the naïve pluripotency gene regulatory network.
Project description:We recently identified ISRIB as a potent inhibitor of the integrated stress response (ISR). ISRIB renders cells resistant to the effects of eIF2α phosphorylation and enhances long-term memory in rodents (10.7554/eLife.00498). Here we show by genome-wide in vivo ribosome profiling that translation of a restricted subset of mRNAs is induced upon ISR activation. ISRIB substantially reversed the translational effects elicited by phosphorylation of eIF2α and induced no major changes in translation or mRNA levels in unstressed cells. eIF2α phosphorylation-induced stress granule (SG) formation was blocked by ISRIB. Strikingly, ISRIB addition to stressed cells with pre-formed SGs induced their rapid disassembly, liberating mRNAs into the actively translating pool. Restoration of mRNA translation and modulation of SG dynamics may be an effective treatment of neurodegenerative diseases characterized by eIF2α phosphorylation, SG formation and cognitive loss. Ribosome profiling with paired RNA-seq
Project description:We characterize the hepatic transcriptome of wildtype and Cugpb1 knockout mice at day 3 of life using the Agilent Whole Mouse Genome Oligo Microarray, focusing on the role of Cugbp1 in the differentiation of hepatic stem cells into hepatocytes.
Project description:Transcriptome analysis of hippocampal RNA samples from wild-type, 5xFAD, 5xFAD;eIF2α+/S51A and eIF2α+/S51A mice Our transcriptome analyses showed clear transcriptional alterations in hippocampi of 5xFAD compared to wild type mice that were not corrected by the eIF2αS51A allele. Hemizygous 5xFAD mice, which were on a genetic background of B6/SJL, were crossed with eIF2α+/S51A mice (C57BL/6J background), to generate the offspring that was analyzed in the microarray. Hippocampal samples of 12 mice (4 groups: wild-type, 5xFAD, 5xFAD;eIF2α+/S51A and eIF2α+/S51A) were processed using Affymetrix Mouse Exon 1.0 ST platform. Array data was processed by Affymetrix Exon Array Computational Tool. No technical replicates were performed.
Project description:Translational control of gene expression is an important regulator of adult stem cell quiescence, activation and self-renewal. In skeletal muscle, quiescent satellite cells maintain low levels of protein synthesis, mediated in part through the phosphorylation of eIF2α (P-eIF2α). Pharmacological inhibition of the eIF2α phosphatase with the small molecule sal003 maintains P-eIF2α and permits the expansion of satellite cells ex vivo. Paradoxically, P-eIF2α also increases the translation of specific mRNAs, which is mediated by P-eIF2α-dependent read-through of inhibitory upstream open reading frames (uORFs). Here, we ask whether P-eIF2α-dependent mRNA translation enables expansion of satellite cells. Using transcriptomic and proteomic analyses, we show a number of genes associated with the assembly of the spindle pole to be upregulated at the level of protein, without corresponding change in mRNA levels, in satellite cells expanded in the presence of sal003. We show that uORFs in the 5′ UTR of mRNA for the mitotic spindle stability gene Tacc3 direct P-eIF2α-dependent translation. Satellite cells deficient for TACC3 exhibit defects in expansion, self-renewal and regeneration of skeletal muscle.
Project description:To study the impact of p-eIF2α reduction in excitatory neurons on translational landscape, we performed both excitatory neuron-specific translational profiling and general proteomic analysis in the dorsal hippocampus of eIF2α cKICaMKIIα and control mice under basal conditions and following learning.