Polysome Profiling in Isoleucine tRNA Isoswitch Cells
Ontology highlight
ABSTRACT:
ORGANISM(S): Homo sapiens
PROVIDER: GSE172349 | GEO | 2023/04/01
REPOSITORIES: GEO
Similar Datasets
Project description:Ribosome Profiling was used to evaluated whether changes in abundance of tRNAIleUAU and tRNAIleGAU would affect codon dependent translation and quantify dwell times over isoleucyl codons
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Project description:To associate the amount of tRNAs with codon usage, we perform hydro-tRNA sequencing (Gogakos et al. 2017) and quantify tRNA expression in HEK293 and HeLa cells.
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Project description:Polysome Profiling in Isoleucine tRNA Isoswitch Cells
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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 translation depends on mRNA-specific initiation, elongation, and termination rates. While the regulation of ribosome elongation is well studied in bacteria and yeast, less is known in higher eukaryotes. Here, we combined ribosome and tRNA profiling to investigate the relations between ribosome elongation rates, (aminoacyl-) tRNA levels and codon usage in mammals. We modeled codon-specific ribosome dwell times and translation fluxes from ribosome profiling, considering pair-interactions between ribosome sites. In mouse liver, the model revealed site and codon specific dwell times, as well as codon pair-interactions clustering by amino acids. While translation fluxes varied significantly across diurnal time and feeding regimen, codon dwell times were highly stable, and conserved in human. Fasting had no effect on codon dwell times in mouse liver. Profiling of total and aminoacylated tRNAs revealed highly heterogeneous levels with specific isoacceptor patterns and a correlation with codon usage. tRNAs for isoleucine, asparagine, aspartate and arginine were lowly loaded and conserved in fasted mice. Finally, codons with low levels of charged tRNAs and high codon usage relative to tRNA abundance exhibited long dwell times. Together, these analyses pave the way towards understanding the complex relation between tRNA loading, codon usage and ribosome dwell times in mammals.
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Project description:Polysome-profiling is commonly used to study translatomes, i.e. transcriptome-wide patterns of translational efficiency. The standard approach for collecting efficiently translated polysome-associated RNA results in laborious extraction of RNA from a large volume across many fractions. This property makes polysome-profiling inconvenient for larger experimental designs or samples with low RNA amounts such as primary cells or frozen tissues. To address this, we optimized a non-linear sucrose gradient which reproducibly enriches for mRNAs associated with >3 ribosomes in only one or two fractions, thereby reducing sample handling 5-10 fold. The technique can be applied to frozen tissue samples from biobanks, and generates polysome-associated RNA with a quality reflecting the starting material. When coupled with smart-seq2, a single-cell RNA sequencing technique, translatomes from small tissue samples can be obtained. Translatomes acquired using optimized non-linear gradients resemble those obtained with the standard approach employing linear gradients. Polysome-profiling using optimized non-linear gradients in serum starved HCT-116 cells with or without p53 showed that p53 status associated with changes in mRNA abundance and translational efficiency leading to changes in protein levels. Moreover, p53 status also induced translational buffering whereby changes in mRNA levels are buffered at the level of mRNA translation to maintain protein levels constant. Thus, here we present a polysome-profiling technique applicable to large study designs, primary cells and frozen tissue samples such as those collected in bio banks.
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Project description:RNA bisulfite sequencing for polysome fractions
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Project description:Protein translation depends on mRNA-specific initiation, elongation, and termination rates. While the regulation of ribosome elongation is well studied in bacteria and yeast, less is known in higher eukaryotes. Here, we combined ribosome and tRNA profiling to investigate the relations between ribosome elongation rates, (aminoacyl-) tRNA levels and codon usage in mammals. We modeled codon-specific ribosome dwell times and translation fluxes from ribosome profiling, considering pair-interactions between ribosome sites. In mouse liver, the model revealed site and codon specific dwell times, as well as codon pair-interactions clustering by amino acids. While translation fluxes varied significantly across diurnal time and feeding regimen, codon dwell times were highly stable, and conserved in human. Fasting had no effect on codon dwell times in mouse liver. Profiling of total and aminoacylated tRNAs revealed highly heterogeneous levels with specific isoacceptor patterns and a correlation with codon usage. tRNAs for isoleucine, asparagine, aspartate and arginine were lowly loaded and conserved in fasted mice. Finally, codons with low levels of charged tRNAs and high codon usage relative to tRNA abundance exhibited long dwell times. Together, these analyses pave the way towards understanding the complex relation between tRNA loading, codon usage and ribosome dwell times in mammals.
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Project description:We followed the polysomal association of maternal and early zygotic transcriptome over the first few hours of embryonic development, prior to and after MBT. We isolated polysome-associated (bound) and non-polysome-associated (unbound) mRNAs using sucrose gradient centrifugation followed by size fractionation. Using next generation sequencing (RNA-seq), we profiled the transcriptome in polysome-bound and unbound fractions. Our analysis revealed distinct dynamics of polysome association of cytoplasmically polyadenylated maternal mRNAs.
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