Ribosome Profiling Reveals Pervasive Translation Outside of Annotated Protein-Coding Genes
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ABSTRACT:
ORGANISM(S): Mus musculus Homo sapiens
PROVIDER: GSE60095 | GEO | 2014/08/21
SECONDARY ACCESSION(S): PRJNA257463
REPOSITORIES: GEO
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Project description:Ribosome profiling suggests that ribosomes occupy many regions of the transcriptome thought to be non-coding, including 5' UTRs and lncRNAs. Apparent ribosome footprints outside of protein-coding regions raise the possibility of artifacts unrelated to translation, particularly when they occupy multiple, overlapping open reading frames (ORFs). Here we show hallmarks of translation in these footprints: co-purification with the large ribosomal subunit, response to drugs targeting elongation, trinucleotide periodicity, and initiation at early AUGs. We develop a metric for distinguishing between 80S footprints and nonribosomal sources using footprint size distributions, which validates the vast majority of footprints outside of coding regions. We present evidence for polypeptide production beyond annotated genes, including induction of immune responses following human cytomegalovirus (HCMV) infection. Translation is pervasive on cytosolic transcripts outside of conserved reading frames, and direct detection of this expanded universe of translated products enables efforts to understand how cells manage and exploit its consequences. Ribosome profiling to verify that true ribosome footprints shift in response to different elongation inhibitors (CHX vs Emetine) and co-purify with an affinity-tagged large ribosomal subunit (bound vs input)
2014-08-21 | E-GEOD-60095 | biostudies-arrayexpress
Project description:Recent studies highlight the importance of translational control in determining protein abundance, underscoring the value of measuring gene expression at the level of translation. We present a protocol for genome-wide, quantitative analysis of in vivo translation by deep sequencing. This ribosome profiling approach maps the exact positions of ribosomes on transcripts by nuclease footprinting. The nuclease-protected mRNA fragments are converted into a DNA library suitable for deep sequencing using a strategy that minimizes bias. The abundance of different footprint fragments in deep sequencing data reports on the amount of translation of a gene. Additionally, footprints reveal the exact regions of the transcriptome that are translated. To better define translated reading frames, we describe an adaptation that reveals the sites of translation initiation by pre-treating cells with harringtonine to immobilize initiating ribosomes. The protocol we describe requires 5 - 7 days to generate a completed ribosome profiling sequencing library. Ribosome profiling in cultured mammalian cells under three different footprinting conditions
2012-07-26 | E-GEOD-37744 | biostudies-arrayexpress
Project description:Ribosome profiling revealed translation outside of canonical coding sequences (CDSs) including translation of short upstream open-reading frames (ORFs), long non-coding RNAs, ORFs in UTRs or ORFs in alternative reading frames. Ribo-seq but also bioinformatics-based prediction and RNA-sequencing reported translation of thousands of ORFs derived from non-translated regions (NTRs). Although such ORFs gained increased attention over the years, their actual coding potential remains debated as protein products of only a fraction of them were identified by mass spectrometry. Here, we introduced a new workflow to discover translation products of NTRs at a large-scale. We combined reducing sample complexity (by enriching N-terminal peptides of cytosolic proteins as such peptides are ideal proxies for translation) with and extend search space (combining the sequences of UniProt proteins, UniProt isoforms and publicly available Ribo-seq data) reasoning that this combination increased chances of identifying proteins from NTRs. Further, we introduced rigorous data analysis and results curation workflows to cope with the increased complexity of the search space and to mine identified peptides. This stringent filtering approach was found essential to retain confident translational evidence at the peptide level for NTRs. We show that theoretically our strategy facilitates the detection of translation events of transcripts from NTRs, but experimentally less than 1% of all identified peptides might originate from such translation events.
2022-07-12 | PXD030601 | Pride
Project description:Fully assembled ribosomes exist in two populations: polysomes and monosomes. While the former has been studied extensively, to what extent translation occurs on monosomes and its importance for overall translational output remains controversial. Here, we used ribosome profiling to examine the translational status of 80S monosomes in Saccharomyces cerevisiae. We found that the vast majority of 80S monosomes are elongating, not initiating. Further, most mRNAs exhibit some degree of monosome occupancy, with monosomes predominating on nonsense-mediated decay (NMD) targets, upstream open reading frames (uORFs), canonical ORFs shorter than ~590 nucleotides and ORFs for which the total time required to complete elongation is substantially shorter than that required for initiation. Importantly, mRNAs encoding low-abundance regulatory proteins tend to be enriched in the monosome fraction. Our data highlight the importance of monosomes for the translation of highly regulated mRNAs. We examined the translational status of single 80S ribosomes using ribosome profiling, and compared these monosome footprints to both polysome ribosome footprints and general ribosome profiling. RNASeq libraries were also prepared from the overall sample input.
2016-02-11 | E-GEOD-76117 | biostudies-arrayexpress
Project description:Accurate annotations of protein coding regions are essential for understanding how genetic information is translated into biological functions. The recent development of ribosome footprint profiling provides an important new tool for measuring translation. Here we describe riboHMM, a new method that uses ribosome footprint data along with gene expression and sequence information to accurately infer translated sequences. We applied our method to human lymphoblastoid cell lines and identified 7,863 previously unannotated coding sequences, including 445 translated sequences in pseudogenes and 2,442 translated upstream open reading frames. We observed an enrichment of harringtonine-treated ribosome footprints at the inferred initiation sites, validating many of the novel coding sequences. In aggregate, the novel sequences exhibit significant signatures of purifying selection indicative of protein-coding function, suggesting that many of the novel sequences are functional. We observed that nearly 40% of bicistronic transcripts showed significant negative correlation in the levels of translation of their two coding sequences, suggesting a key regulatory role for these novel translated sequences. Despite evidence for their functional importance, the novel peptide sequences were detected by mass spectrometry at a lower rate than predicted based on data from annotated proteins, thus suggesting that many of the novel peptide products may be relatively short-lived. Our work illustrates the value of ribosome profiling for improving coding annotations, and significantly expands the set of known coding regions.
2015-12-25 | GSE75290 | GEO
Project description:Ribosome profiling has revealed translation outside of canonical coding sequences (CDSs) including translation of short upstream ORFs, long non-coding RNAs, overlapping ORFs, ORFs in UTRs or ORFs in alternative reading frames. Studies combining mass spectrometry, ribosome profiling and CRISPR-based screens showed that hundreds of ORFs derived from non-coding transcripts produce (micro)proteins, while other studies failed to find evidence for such types of non-canonical translation products. Here, we attempted to discover translation products from non-coding regions by strongly reducing the complexity of the sample prior to mass spectrometric analysis. We used an extended database as the search space and applied stringent filtering of the identified peptides to find evidence for novel translation events. Theoretically, we show that our strategy facilitates the detection of translation events of transcripts from non-coding regions, but experimentally only find 19 peptides (less than 1% of all identified peptides) that might originate from such translation events. However, curation and stringent validation further reduces this to 10 reliable identifications. The fragmentation of these 10 peptides was further validated by comparison with the fragmentation of synthetic peptides.
2022-08-02 | PXD030285 | panorama
Project description:Ribosome profiling has revealed translation outside of canonical coding sequences (CDSs) including translation of short upstream ORFs, long non-coding RNAs, overlapping ORFs, ORFs in UTRs or ORFs in alternative reading frames. Studies combining mass spectrometry, ribosome profiling and CRISPR-based screens showed that hundreds of ORFs derived from non-coding transcripts produce (micro)proteins and might be functional, while other studies failed to find evidence for such types of non-canonical translation events. In this study we tried to detect (and characterize) proteins originating from these non-translated regions (NTRs). We attempted to discover translation products from non-coding regions at large scale by reducing the overall sample complexity (by enriching cytosolic N-terminal peptides) and combined it with an extend search space (combining UniProt proteins, UniProt isoforms and publicly available Ribo-seq data). Reasoning that this strategy would increase the likelihood of identifying proteins from NTRs. Further, we introduced rigorous data analysis and results curation workflows. This stringent filtering approach was found essential to retain confident translational evidence at the peptide level for NTRs. We show that, theoretically, our strategy facilitates the detection of translation events of transcripts from NTRs, but experimentally we find that less than 1% of all identified peptides might originate from such translation events. However, one NTR protein was further characterized by Virotrap based interaction analysis. This resulted in several potential interaction partners associated with membranes and vesicle transport. Showing that the non-translated regions that do result in proteins might be functional.
2022-07-12 | PXD030216 | Pride
Project description:Ribosome profiling and high-throughput sequencing provide unprecedented opportunities for the analysis of mRNA translation. Using this novel method, several studies have demonstrated the widespread role of short upstream reading frames in translational control as well as slower elongation at the beginning of open reading frames in response to stress. Based on the initial studies, the importance of adding or omitting translation inhibitors, such as cycloheximide, was noted as it markedly affected ribosome coverage profiles. For that reason, many recent studies omitted translation inhibitors in the culture medium. Here, we investigate the influence of ranging cycloheximide concentrations on ribosome profiles in Saccharomyces cerevisiae and demonstrate that increasing the drug concentration can overcome some of the artifacts. We subjected cells to various manipulations and show that neither oxidative stress nor heat shock nor amino acid starvation affect translation elongation. Instead, the observations in the initial studies are the result of cycloheximide-inflicted artifacts. Likewise, we find little support for short upstream reading frames to be involved in wide-spread protein synthesis regulation under stress conditions. Our study highlights the need for better standardization of ribosome profiling methods. Ranging concentrations of cycloheximide and various stress contitions were tested with Ribo-seq
2014-08-01 | E-GEOD-59573 | biostudies-arrayexpress
Project description:Ribosome-footprint profiling provides genome-wide snapshots of translation, but technical challenges can confound its analysis. Here, we use improved methods to obtain ribosome-footprint profiles and mRNA abundances that more faithfully reflect gene expression in Saccharomyces cerevisiae. Our results support proposals that both the beginning of coding regions and codons matching rare tRNAs are more slowly translated. They also indicate that emergent polypeptides with as few as three basic residues within a 10-residue window tend to slow translation. With the improved mRNA measurements, the variation attributable to translational control in exponentially growing yeast was less than previously reported, and most of this variation could be predicted with a simple model that considered mRNA abundance, upstream open reading frames, cap-proximal structure and nucleotide composition, and lengths of the coding and 5'-untranslated regions. Collectively, our results provide a framework for executing and interpreting ribosome-profiling studies and reveal key features of translational control in yeast. Ribosome-footprint profiling and RNA-seq (total RNA, poly(A) selected, RiboMinus treated, or Ribo-Zero treated) from log-phase S. cerevisiae. The study includes a reanalysis of the two Samples from GSE53313. The reanalyzed data is linked to the Series record.
2016-02-10 | E-GEOD-75897 | biostudies-arrayexpress
Project description:Recent studies highlight the importance of translational control in determining protein abundance, underscoring the value of measuring gene expression at the level of translation. We present a protocol for genome-wide, quantitative analysis of in vivo translation by deep sequencing. This ribosome profiling approach maps the exact positions of ribosomes on transcripts by nuclease footprinting. The nuclease-protected mRNA fragments are converted into a DNA library suitable for deep sequencing using a strategy that minimizes bias. The abundance of different footprint fragments in deep sequencing data reports on the amount of translation of a gene. Additionally, footprints reveal the exact regions of the transcriptome that are translated. To better define translated reading frames, we describe an adaptation that reveals the sites of translation initiation by pre-treating cells with harringtonine to immobilize initiating ribosomes. The protocol we describe requires 5 - 7 days to generate a completed ribosome profiling sequencing library.
2012-07-26 | GSE37744 | GEO