Project description:Protein synthesis is strictly regulated during replicative aging in yeast, but global translational regulation during replicative aging is poorly characterized. To conduct ribosomal profiling during replicative aging, we collected a large number of dividing aged cells using a miniature chemostat aging device. Translational efficiency, defined as the number of ribosome footprints normalized to transcript abundance, was compared between young and aged cells for each gene. We identified more than 700 genes with changes greater than twofold during replicative aging. Increased translational efficiency was observed in genes involved in DNA repair and chromosome organization. Decreased translational efficiency was observed in genes encoding ribosome components, transposon Ty1 and Ty2 genes, transcription factor HAC1 genes associated with the unfolded protein response, genes involved in cell wall synthesis and assembly, and ammonium permease genes. Our results provide a global view of translational regulation during replicative aging, in which the pathways involved in various cell functions are translationally regulated and cause diverse phenotypic changes.
Project description:To survey translational efficiency in DRG tissues, we examined translation using ribosome profiling and RNA abundance using RNA-seq. This dataset provides a baseline measurment for protein synthesis rates in murine DRG tissues.
Project description:To survey translational efficiency in DRG tissues, we examined translation using ribosome profiling and RNA abundance using RNA-seq. This dataset provides a baseline measurment for protein synthesis rates in murine DRG tissues.
Project description:Gene expression regulation in eukaryotes is a multi-level process, including transcription, mRNA translation, and protein turnover. Many studies have reported the sophisticated transcriptional regulations during neural development, but the global translational dynamics is still ambiguous. Here, we differentiated human embryonic stem cells (ESCs) into neural progenitor cells (NPCs) with high efficiency and performed ribosome sequencing and RNA sequencing on both ESCs and NPCs. Data analysis revealed that translational controls engaged in many critical pathways and contributed significantly to neural fate determination regulation. Furthermore, we showed that the sequence characteristics in the untranslated region (UTR) might regulate translation efficiency. Specifically, genes with short 5UTR and intense Kozak sequence are associated with high translation efficiency in human ESCs, while genes with long 3'UTR are related to high translation efficiency in NPCs. In addition, we identified four biasedly-used codons (GAC, GAT, AGA, and AGG) and dozens of short open reading frames during neural progenitor differentiation. Thus, our study reveals the translational landscape during early human neural differentiation and provides insights into the regulation of cell fate determination at the translational level.
2023-03-04 | GSE208082 | GEO
Project description:Ramp region influence on translation efficiency in E.coli
Project description:During mRNA translation, tRNAs are charged by aminoacyl-tRNA synthetases (aaRS) and subsequently used by ribosomes. A multi-enzyme aminoacyl-tRNA synthetase complex (MSC) has long been proposed to increase protein synthesis efficiency by passing charged tRNAs directly to ribosomes. An alternative is that the MSC repurposes specific synthetases for ex-translational functions that are activated by cues that direct specific enzymes to novel targets. To explore this question, we generated mammalian cell clones in which ArgRS and GlnRS were absent from the MSC to give a stable complex lacking the two enzymes (MSCΔRQ). Protein synthesis, under a variety of stress conditions, was unchanged in MSCΔRQ cells. Most strikingly, levels of charged tRNAGln and tRNAArg remained unchanged and no ribosome pausing was observed at codons for Arg and Gln. Thus, increasing or regulating protein synthesis efficiency is not dependent on ArgRS and GlnRS in the MSC. Alternatively, and consistent with previously reported ex-translational roles, we found manipulations that do not affect protein synthesis but instead MSC cellular localization.
Project description:In response to pathogenic threats, naïve T cells rapidly transition from a quiescent to activated state, yet the underlying mechanisms are incompletely understood. Using a pulsed SILAC approach, we investigated the dynamics of mRNA translation kinetics and protein turnover in human naïve and activated T cells. Our datasets uncovered that transcription factors maintaining T cell quiescence had constitutively high turnover, which facilitated their depletion upon activation. Furthermore, naïve T cells maintained a surprisingly large number of idling ribosomes as well as 242 repressed mRNA species and a reservoir of glycolytic enzymes. These components were rapidly engaged following stimulation, promoting an immediate translational and glycolytic switch to ramp up the T cell activation program. Our data elucidate new insights into how T cells maintain a prepared state to mount a rapid immune response, and provide a resource of protein turnover, absolute translation kinetics and protein synthesis rates in T cells (www.immunomics.ch).
Project description:Translational control is a widespread mode of gene regulation in organisms ranging from bacteria to mammals. Computational models posit that translational control of protein expression during elongation is exerted through a traffic jam of multiple ribosomes at ribosome pause sites on mRNAs. Yet neither the in vivo frequency of ribosome traffic jams nor the contribution of such traffic jams to protein expression has been measured in any organism. Here we show that upon starvation for single amino acids in the bacterium Escherichia coli, ribosome traffic jams are pervasive across the transcriptome, but they occur at only a subset of codons cognate to the limiting amino acid, and their severity is determined by the translation efficiency of mRNAs. Surprisingly, a computational model based on the observed traffic jams at ribosome pause sites is quantitatively inconsistent with measured protein synthesis rates. By comparison, a model incorporating abortion of protein synthesis at ribosome pause sites in addition to ribosome traffic jams predicts protein synthesis rate with higher accuracy. Consistent with the latter model, a significant fraction of the nascent polypeptides at ribosome pause sites is degraded through the activity of the transfer-messenger RNA during amino acid starvation in E. coli. Our work provides a minimal, experimentally-constrained model for predicting protein expression from ribosome dynamics, and it suggests the existence of a trade-off between the cellular translational capacity and the processivity of protein synthesis in vivo. 6 samples for ribosome profiling and 5 samples for total mRNA profiling
Project description:Translational regulation is of paramount importance for proteome remodeling during stem cell differentiation both at the global and transcript-specific level. In this study, we characterized translational remodeling during hepatogenic differentiation of induced pluripotent stem cells (iPSCs) by polysome profiling. We demonstrate that protein synthesis increases during the initial exit from pluripotency, but is then globally repressed during later steps of hepatogenic maturation. This global downregulation of translation is accompanied by a decrease in the protein abundance of components of the translation machinery, which involves a global reduction in translational efficiency of terminal oligopyrimidine tract (TOP) mRNA encoding translation-related factors. Despite global translational repression during hepatogenic differentiation, key hepatogenic genes remain efficiently translated, and the translation of several transcripts involved in hepato-specific functions and metabolic maturation are even induced. We conclude that, during hepatogenic differentiation, a global decrease in protein synthesis is accompanied by a specific translational rewiring towards hepato-specific transcripts.