Transcriptome-wide sites of collided ribosomes reveal sequence determinants of translational pausing in vivo
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE134541 | GEO | 2020/06/18
REPOSITORIES: GEO
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Project description:Recent studies have revealed that the mRNA translation is punctuated by ribosomal pauses through the body of transcripts. However, little is known about its physiological significance and regulatory aspects. Here we present a multi-dimensional ribosome profiling approach to quantify the dynamics of initiation and elongation of 80S ribosomes across the entire transcriptome in mammalian cells. We show that a subset of transcripts have a significant pausing of 80S ribosome around the start codon, creating a major barrier to the commitment of translation elongation. Intriguingly, genes encoding ribosome proteins themselves exhibit an exceptionally high initiation pausing on their transcripts. Our studies also reveal that the initiation pausing is dependent on the 5’ untranslated region (5’ UTR) of mRNAs and subject to the regulation of mammalian target of rapamycin complex 1 (mTORC1). Thus, the initiation pausing of 80S ribosome represents a novel regulatory step in translational control mediated by nutrient signaling pathway. Untreated TSC2 WT MEFs, TSC2 KO MEFs and TSC2 WT MEFs, TSC2 KO MEFs treated with 20nM rapamycin for 30 minutes or 3hours were harvested for ribosme profiling. The fraction samples were pooled into three groups based on velocity sedimentation: single ribosome fraction (Small group), fractions with 2 ~ 4 ribosomes (Medium group), and the one with ≥5 ribosomes (Large group). RNA were extracted from the whole cell lysis and each fraction group.
2011-11-12 | E-GEOD-25331 | biostudies-arrayexpress
Project description:Protein synthesis by ribosomes takes place on a linear substrate but at variable speeds. Transient pausing of ribosomes can impact a variety of co-translational processes, including protein targeting and folding. These pauses are influenced by the sequence of the mRNA. Thus redundancy in the genetic code allows the same protein to be translated at different rates. However, our knowledge of both the position and the mechanism of translational pausing in vivo is highly limited. Here we present a genome-wide analysis of translational pausing in bacteria using ribosome profiling-deep sequencing of ribosome-protected mRNA fragments. This approach enables high-resolution measurement of ribosome density profiles along most transcripts at unperturbed, endogenous expression levels. Unexpectedly, we found that codons decoded by rare tRNAs do not lead to slow translation under nutrient-rich conditions. Instead, Shine-Dalgarno-(SD) like features within coding sequences cause pervasive translational pausing. Using an orthogonal ribosome possessing an altered anti-SD sequence, we demonstrated that pausing is due to hybridization between mRNA and the 16S rRNA of the translating ribosome. In protein coding sequences, internal SD sequences are disfavoured, which leads to biased usage, avoiding codons and codon pairs that resemble canonical SD sites. Our results indicate that internal SD-like sequences are a major determinant of translation rates and a global driving force for the coding of bacterial genomes. Identification of translation pause sites in vivo using ribosome profiling
2012-04-01 | E-GEOD-35641 | biostudies-arrayexpress
Project description:The regulation of translation elongation plays a vital role in protein folding; an adequate translational pause provides time and cellular environments for the co-translational folding of nascent peptides. However, the genomic landscape, sequence determinants, and molecular consequences of translational pausing remain mostly unknown. In this study, we performed disome-seq that sequenced mRNA fragments protected by two consecutive ribosomes – a product of severe translational pauses during which the upstream ribosome collides into the paused one. We detected severe translational pauses on ~75% of yeast genes. These pauses were often explained by one of the three mechanisms: 1) slow ribosome releasing at stop codons, 2) slow peptide formation from proline, glycine, asparagine, and cysteine, and 3) slow leaving of polylysine from the exit tunnel of ribosomes. Notably, these amino acids also terminate the α-helical conformation. Such dual roles of amino acids establish an inborn coupling between the synthetic completion of a structural motif and a translational pause. Furthermore, paused ribosomes often recruit chaperones to assist protein folding. As a consequence, emergent protein structures during evolution should be ready to be correctly folded. Collectively, our study shows widespread translational pauses and sheds lights on a better understanding of the regulation of co-translational protein folding.
2020-12-10 | PXD015271 | Pride
Project description:Recent studies have revealed that the mRNA translation is punctuated by ribosomal pauses through the body of transcripts. However, little is known about its physiological significance and regulatory aspects. Here we present a multi-dimensional ribosome profiling approach to quantify the dynamics of initiation and elongation of 80S ribosomes across the entire transcriptome in mammalian cells. We show that a subset of transcripts have a significant pausing of 80S ribosome around the start codon, creating a major barrier to the commitment of translation elongation. Intriguingly, genes encoding ribosome proteins themselves exhibit an exceptionally high initiation pausing on their transcripts. Our studies also reveal that the initiation pausing is dependent on the 5M-bM-^@M-^Y untranslated region (5M-bM-^@M-^Y UTR) of mRNAs and subject to the regulation of mammalian target of rapamycin complex 1 (mTORC1). Thus, the initiation pausing of 80S ribosome represents a novel regulatory step in translational control mediated by nutrient signaling pathway. Monitor the translational status of transcriptome in mammalian cells under different conditions
2011-11-12 | E-GEOD-25626 | biostudies-arrayexpress
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
2014-05-15 | E-GEOD-51052 | biostudies-arrayexpress
Project description:Ribosome pausing slows down translation and can affect protein synthesis. Improving translation efficiency can therefore be of commercial value. Here, we investigated the occurrence of ribosome pausing during amylase secretion by the industrial production organism Bacillus subtilis under semi fed-batch fermentation conditions. We first assessed our ribosome profiling setup by inducing ribosome stalling at isoleucine codons using the antibiotic mupirocin, and found a pause preference for isoleucine codons preceded by E and P site codons with guanosine residues in their first nucleotide position. Interestingly, when we applied standard ribosomal profiling conditions we found again an enrichment of guanosine residues in the E and P site of ribosome pause sites, but this time also upstream of the ribosome pause site. This sequence motif deviates from previously described ribosome pausing motifs. For the highly expressed amylase gene amyM several strong ribosome pausing sites were detected, which remained present during the 64-hour long fermentation, and were neither related to rare codons nor to secondary protein structures. When surveying the genome, an interesting finding was the presence of strong ribosome pausing sites in several toxins genes. These potential ribosome stall sites may function in preventing inadvertent activity in the cytosol.
2024-01-01 | GSE250313 | GEO
Project description:Ribosome pausing slows down translation and can affect protein synthesis. Improving translation efficiency can therefore be of commercial value. Here, we investigated the occurrence of ribosome pausing during amylase secretion by the industrial production organism Bacillus subtilis under semi fed-batch fermentation conditions. We first assessed our ribosome profiling setup by inducing ribosome stalling at isoleucine codons using the antibiotic mupirocin, and found a pause preference for isoleucine codons preceded by E and P site codons with guanosine residues in their first nucleotide position. Interestingly, when we applied standard ribosomal profiling conditions we found again an enrichment of guanosine residues in the E and P site of ribosome pause sites, but this time also upstream of the ribosome pause site. This sequence motif deviates from previously described ribosome pausing motifs. For the highly expressed amylase gene amyM several strong ribosome pausing sites were detected, which remained present during the 64-hour long fermentation, and were neither related to rare codons nor to secondary protein structures. When surveying the genome, an interesting finding was the presence of strong ribosome pausing sites in several toxins genes. These potential ribosome stall sites may function in preventing inadvertent activity in the cytosol.
2024-01-01 | GSE250312 | GEO
Project description:Oxidative stress causes K63-linked ubiquitination of ribosomes by the E2 ubiquitin conjugase, Rad6. How Rad6-mediated ubiquitination of ribosomes affects translation, however, is unclear. We therefore performed Ribo-seq and Disome-seq in Saccharomyces cerevisiae, and found that oxidative stress caused ribosome pausing at specific amino acid motifs, and this also led to ribosome collisions. However, these redox pausing signatures were lost in the absence of Rad6 but did not depend on the ribosome-associated quality control (RQC) pathway. We also found that Rad6 is needed to inhibit overall translation in response to oxidative stress and its deletion leads to increased expression of antioxidant genes. Finally, we observed that the lack of Rad6 leads to changes during translation initiation that affect activation of the integrated stress response (ISR) pathway. Our results provide a high-resolution picture of the gene expression changes during oxidative stress and unravel an additional stress response pathway affecting translation elongation.
2023-08-22 | GSE226082 | GEO
Project description:In protein synthesis, ribosome movement is not always smooth, rather often impeded by numerous reasons. Although the deceleration of ribosome defines the fates of the mRNAs and the synthesizing proteins, fundamental questions remain to be addressed including where ribosomes pause in mRNAs, what kind of RNA/amino acid context causes the pausing, and how physiologically significant the slowdown of protein synthesis is. Here we surveyed the position of ribosome collisions, caused by ribosome pausing, at a genome-wide level using the modified ribosome profiling in human and zebrafish. The collided ribosomes, i.e. disome, emerge at various sites; the proline-proline-lysine motif, stop codons, and 3′ UTR. The number of ribosomes in a collision is not limited to two, rather four to five, forming a queue of ribosomes. Especially, XBP1, a key modulator of unfolded protein response, shows striking queues of collided ribosomes thus acts as a substrate for ribosome-associated quality control (RQC) to avoid the accumulation of undesired proteins in the absence of stress. Our results provide an insight into the causes and the consequences of ribosome slowdowns by dissecting the specific architecture of ribosomes.
2020-05-05 | GSE140639 | GEO
Project description:In protein synthesis, ribosome movement is not always smooth, rather often impeded by numerous reasons. Although the deceleration of ribosome defines the fates of the mRNAs and the synthesizing proteins, fundamental questions remain to be addressed including where ribosomes pause in mRNAs, what kind of RNA/amino acid context causes the pausing, and how physiologically significant the slowdown of protein synthesis is. Here we surveyed the position of ribosome collisions, caused by ribosome pausing, at a genome-wide level using the modified ribosome profiling in human and zebrafish. The collided ribosomes, i.e. disome, emerge at various sites; the proline-proline-lysine motif, stop codons, and 3′ UTR. The number of ribosomes in a collision is not limited to two, rather four to five, forming a queue of ribosomes. Especially, XBP1, a key modulator of unfolded protein response, shows striking queues of collided ribosomes thus acts as a substrate for ribosome-associated quality control (RQC) to avoid the accumulation of undesired proteins in the absence of stress. Our results provide an insight into the causes and the consequences of ribosome slowdowns by dissecting the specific architecture of ribosomes.
2020-05-05 | GSE133393 | GEO