Optimization of codon translation rates via tRNA modifications maintains proteome integrity
Ontology highlight
ABSTRACT:
ORGANISM(S): Caenorhabditis elegans Saccharomyces cerevisiae
PROVIDER: GSE67387 | GEO | 2015/06/04
SECONDARY ACCESSION(S): PRJNA279785
REPOSITORIES: GEO
Similar Datasets
Project description:Proteins begin to fold as they emerge from translating ribosomes. The kinetics of ribosome transit along a given mRNA can influence nascent chain folding, but the extent to which individual codon translation rates impact proteome integrity remains unknown. Here, we show that slower decoding of discrete codons elicits widespread protein aggregation in vivo. Using ribosome profiling, we find that loss of anticodon wobble uridine (U34) modifications in a subset of tRNAs leads to ribosome pausing at their cognate codons in S. cerevisiae and C. elegans. Yeast cells lacking U34 modifications exhibit gene expression hallmarks of proteotoxic stress and accumulate aggregates of endogenous proteins with key cellular functions. Moreover, these cells are severely compromised in clearing stress-induced protein aggregates. Overexpression of hypomodified tRNAs alleviates ribosome pausing, concomitantly restoring protein homeostasis. Our findings demonstrate that modified U34 is an evolutionarily conserved accelerator of decoding and reveal an unanticipated role for tRNA anticodon modifications in maintaining proteome integrity. Ribosome profiling of wild-type and tRNA modification-deficient yeast and nematodes. Yeast samples were generated in various growth conditions (rich medium versus stress induced by treatment with diamide or rapamycin) and paired mRNA-Seq was performed on a subset of samples. Dataset contains three biological replicates for yeast samples and two biological replicates for nematode samples.
2015-06-04 | E-GEOD-67387 | biostudies-arrayexpress
Project description:Some codons of the genetic code can be read not only by cognate, but also by near-cognate tRNAs. This flexibility is thought to be conferred mainly by a mismatch between the third base of the codon and the first of the anticodon (the so-called wobble position). However, this simplistic explanation underestimates the importance of nucleotide modifications in the decoding process. Using a system in which only near-cognate tRNAs can decode a specific codon, we investigated the role of six modifications of the anticodon, or adjacent nucleotides, of the tRNAs specific for Tyr, Gln, Lys, Trp, Cys and Arg in Saccharomyces cerevisiae. Modifications almost systematically rendered these tRNAs able to act as near-cognate tRNAs at stop codons, even though they involve non-canonical base-pairs, without markedly affecting their ability to decode cognate or near-cognate sense codons. These findings reveal an important effect of modifications to tRNA decoding with implications for understanding the flexibility of the genetic code.
2018-04-04 | GSE108772 | GEO
Project description:Transfer RNA (tRNA) modifications enhance the efficiency, specificity and fidelity of translation in all organisms. The anticodon modification mcm5s2U34 is required for normal growth and stress resistance in yeast; mutants lacking this modification have numerous phenotypes. Mutations in the homologous human genes are linked to neurological disease. The yeast phenotypes can be ameliorated by overexpression of specific tRNAs, suggesting that the modifications are necessary for efficient translation of specific codons. We determined the in vivo ribosome distributions at single codon resolution in yeast strains lacking mcm5s2U. We found accumulations at AAA, CAA, and GAA codons, suggesting that translation is slow when these codons are in the ribosomal A site, but these changes appeared too small to affect protein output. Instead, we observed activation of the GCN4-mediated stress response by a non- canonical pathway. Thus, loss of mcm5s2U causes global effects on gene expression due to perturbation of cellular signaling. WT yeast and mutants lacking anticodon tRNA modifications were grown in YPD, and subjected to ribosome footprint profiling (ribo-seq) and RNA-seq of poly-A selected RNA. Dataset contains biological replicates for WT, Δncs6 and Δuba4. Technical replicates were also performed for all RNA-seq datasets (using a different poly-A selection method).
2013-08-01 | E-GEOD-45366 | biostudies-arrayexpress
Project description:Estrogen receptor alpha (ERα) activity is associated with increased cancer cell proliferation. Studies aiming to understand the impact of ERα on cancer-associated phenotypes have largely been limited to its transcriptional activity. Herein, we demonstrate that ERα coordinates its transcriptional output with selective modulation of mRNA translation. Importantly, translational perturbations caused by depletion of ERα largely manifest as "translational offsetting" of the transcriptome, whereby amounts of translated mRNAs and corresponding protein levels are maintained constant despite changes in mRNA abundance. Transcripts whose levels, but not polysome-association, are reduced following ERα depletion lack features which limit translation efficiency including structured 5'UTRs and miRNA target sites. In contrast, mRNAs induced upon ERα depletion whose polysome-association remains unaltered are enriched in codons requiring U34-modified tRNAs for efficient decoding. Consistently, ERα regulates levels of U34-modifying enzymes and thereby controls levels of U34-modified tRNAs. These findings unravel a hitherto unprecedented mechanism of ERα-dependent orchestration of transcriptional and translational programs that may be a pervasive mechanism of proteome maintenance in hormone-dependent cancers.
2019-09-24 | GSE120916 | GEO
Project description:Estrogen receptor alpha (ERα) activity is associated with increased cancer cell proliferation. Studies aiming to understand the impact of ERα on cancer-associated phenotypes have largely been limited to its transcriptional activity. Herein, we demonstrate that ERα coordinates its transcriptional output with selective modulation of mRNA translation. Importantly, translational perturbations caused by depletion of ERα largely manifest as "translational offsetting" of the transcriptome, whereby amounts of translated mRNAs and corresponding protein levels are maintained constant despite changes in mRNA abundance. Transcripts whose levels, but not polysome-association, are reduced following ERα depletion lack features which limit translation efficiency including structured 5'UTRs and miRNA target sites. In contrast, mRNAs induced upon ERα depletion whose polysome-association remains unaltered are enriched in codons requiring U34-modified tRNAs for efficient decoding. Consistently, ERα regulates levels of U34-modifying enzymes and thereby controls levels of U34-modified tRNAs. These findings unravel a hitherto unprecedented mechanism of ERα-dependent orchestration of transcriptional and translational programs that may be a pervasive mechanism of proteome maintenance in hormone-dependent cancers.
2019-09-24 | GSE120914 | GEO
Project description:Estrogen receptor alpha (ERα) activity is associated with increased cancer cell proliferation. Studies aiming to understand the impact of ERα on cancer-associated phenotypes have largely been limited to its transcriptional activity. Herein, we demonstrate that ERα coordinates its transcriptional output with selective modulation of mRNA translation. Importantly, translational perturbations caused by depletion of ERα largely manifest as "translational offsetting" of the transcriptome, whereby amounts of translated mRNAs and corresponding protein levels are maintained constant despite changes in mRNA abundance. Transcripts whose levels, but not polysome-association, are reduced following ERα depletion lack features which limit translation efficiency including structured 5'UTRs and miRNA target sites. In contrast, mRNAs induced upon ERα depletion whose polysome-association remains unaltered are enriched in codons requiring U34-modified tRNAs for efficient decoding. Consistently, ERα regulates levels of U34-modifying enzymes and thereby controls levels of U34-modified tRNAs. These findings unravel a hitherto unprecedented mechanism of ERα-dependent orchestration of transcriptional and translational programs that may be a pervasive mechanism of proteome maintenance in hormone-dependent cancers.
2019-09-24 | GSE120535 | GEO
Project description:Estrogen receptor alpha (ERα) activity is associated with increased cancer cell proliferation. Studies aiming to understand the impact of ERα on cancer-associated phenotypes have largely been limited to its transcriptional activity. Herein, we demonstrate that ERα coordinates its transcriptional output with selective modulation of mRNA translation. Importantly, translational perturbations caused by depletion of ERα largely manifest as "translational offsetting" of the transcriptome, whereby amounts of translated mRNAs and corresponding protein levels are maintained constant despite changes in mRNA abundance. Transcripts whose levels, but not polysome-association, are reduced following ERα depletion lack features which limit translation efficiency including structured 5'UTRs and miRNA target sites. In contrast, mRNAs induced upon ERα depletion whose polysome-association remains unaltered are enriched in codons requiring U34-modified tRNAs for efficient decoding. Consistently, ERα regulates levels of U34-modifying enzymes and thereby controls levels of U34-modified tRNAs. These findings unravel a hitherto unprecedented mechanism of ERα-dependent orchestration of transcriptional and translational programs that may be a pervasive mechanism of proteome maintenance in hormone-dependent cancers.
2019-09-24 | GSE134606 | GEO
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:Transfer RNA (tRNA) modifications enhance the efficiency, specificity and fidelity of translation in all organisms. The anticodon modification mcm5s2U34 is required for normal growth and stress resistance in yeast; mutants lacking this modification have numerous phenotypes. Mutations in the homologous human genes are linked to neurological disease. The yeast phenotypes can be ameliorated by overexpression of specific tRNAs, suggesting that the modifications are necessary for efficient translation of specific codons. We determined the in vivo ribosome distributions at single codon resolution in yeast strains lacking mcm5s2U. We found accumulations at AAA, CAA, and GAA codons, suggesting that translation is slow when these codons are in the ribosomal A site, but these changes appeared too small to affect protein output. Instead, we observed activation of the GCN4-mediated stress response by a non- canonical pathway. Thus, loss of mcm5s2U causes global effects on gene expression due to perturbation of cellular signaling.
2013-08-01 | GSE45366 | GEO
Project description:Post-transcriptional modification of tRNAs is critical for protein synthesis. Queuosine (Q), a 7-deaza-guanosine derivative, is present at the first position of anticodons of several tRNA species. In vertebrate tRNAs for Tyr and Asp, Q is further glycosylated with galactose and mannose to generate galactosyl-queuosine (galQ) and mannosyl-queuosine (manQ), respectively. However, the biogenesis and physiological relevance of Q-glycosylation remain poorly understood. Here, we biochemically identified two RNA glycosylases, queuosine-tRNA galactosyltransferase (QTGAL) and queuosine-tRNA mannosyltransferase (QTMAN), and successfully reconstituted galQ and manQ formation on the respective tRNAs in the presence of nucleotide diphosphate sugars. Ribosome profiling analyses of human knockout (KO) cells of QTGAL and QTMAN revealed that Q-glycosylation slowed down elongation at the cognate codons, UAC and GAC (GAU), respectively. Furthermore, protein aggregates were significantly increased in both KO cell lines, indicating that Q-glycosylation contributes to proteostasis of nascent proteins. We determined atomic structures of human cytoplasmic tRNAs for Try and Asp bound to the ribosome A-site, providing the molecular basis of codon recognition regulated by galQ and manQ. Furthermore, zebrafish qtgal and qtman KO lines displayed shortened body length, suggesting Q-glycosylation is required for post-embryonic growth in vertebrates. These findings demonstrate that Q-glycosylation modulates codon-specific translation to optimize the decoding speed in protein synthesis, thereby maintaining correct folding of nascent proteins, proteome integrity, and normal growth of vertebrates.
2023-11-21 | GSE213181 | GEO