A subcellular map of translational machinery composition and regulation at the single-molecule level [ALIBi_Nmd3_Gnl3_KD]
Ontology highlight
ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE283892 | GEO | 2025/03/05
REPOSITORIES: GEO
Similar Datasets
Project description:Millions of ribosomes are packed within mammalian cells, yet we lack tools to visualize them in toto and characterize their subcellular composition. Here, we present ribosome expansion microscopy (RiboExM) to visualize individual ribosomes and an optogenetic proximity-labeling technique (ALIBi) to probe their composition. We generated a super-resolution ribosomal map, revealing unexpected subcellular translational hotspots and enrichment of 60S subunits near polysomes at the endoplasmic reticulum (ER). We found that Lsg1 tethers 60S to the ER and regulates translation of select proteins. Additionally, we discovered ribosome heterogeneity at mitochondria guiding translation of metabolism-related transcripts. Finally, we visualized ribosomes in neurons, revealing a dynamic switch between monosomes and polysomes in neuronal translation. Together, these approaches enable exploration of ribosomal localization and composition at unprecedented resolution.
2025-03-05 | GSE283890 | GEO
Project description:Millions of ribosomes are packed within mammalian cells, yet we lack tools to visualize them in toto and characterize their subcellular composition. Here, we present ribosome expansion microscopy (RiboExM) to visualize individual ribosomes and an optogenetic proximity-labeling technique (ALIBi) to probe their composition. We generated a super-resolution ribosomal map, revealing unexpected subcellular translational hotspots and enrichment of 60S subunits near polysomes at the endoplasmic reticulum (ER). We found that Lsg1 tethers 60S to the ER and regulates translation of select proteins. Additionally, we discovered ribosome heterogeneity at mitochondria guiding translation of metabolism-related transcripts. Finally, we visualized ribosomes in neurons, revealing a dynamic switch between monosomes and polysomes in neuronal translation. Together, these approaches enable exploration of ribosomal localization and composition at unprecedented resolution.
2025-03-05 | GSE283888 | GEO
Project description:Millions of ribosomes are packed within mammalian cells, yet we lack tools to visualize them in toto and characterize their subcellular composition. Here, we present ribosome expansion microscopy (RiboExM) to visualize individual ribosomes and an optogenetic proximity-labeling technique (ALIBi) to probe their composition. We generated a super-resolution ribosomal map, revealing unexpected subcellular translational hotspots and enrichment of 60S subunits near polysomes at the endoplasmic reticulum (ER). We found that Lsg1 tethers 60S to the ER and regulates translation of select proteins. Additionally, we discovered ribosome heterogeneity at mitochondria guiding translation of metabolism-related transcripts. Finally, we visualized ribosomes in neurons, revealing a dynamic switch between monosomes and polysomes in neuronal translation. Together, these approaches enable exploration of ribosomal localization and composition at unprecedented resolution.
2025-03-05 | PXD058668 | Pride
Project description:We use mRNA-seq in combination with polysome profiling to determine translational status for all mRNAs in Drosophila mature oocytes and activated eggs. Puromycin-treated lysates are used as a negative control in polysome profiling experiments. Additionally, we use ribosome footprinting to globally measure translational efficiency of mRNAs in wild type mature oocytes as well as wild type and png mutant activated eggs. Lysates of hand-dissected Drosophila mature oocytes (containing ~540 M-NM-<g of total RNA) were subjected to separation by velocity sedimentation through sucrose gradients. In this way, free mRNAs (present in RNPs fraction) or those comigrating with ribosomal subunits (40S or 60S+80S fractions) or with varying numbers of bound ribosomes (low polysomes (2-4 ribosomes), medium polysomes (5-9 ribosomes), and heavy polysomes (more than 10 ribosomes) can be separated based on their size and collected as sucrose gradient fractions. To compare quantitatively the levels of every mRNA across the polysome gradient fractions, we added 5ng of S. cerevisiae mRNA as an exogenous spike-in to each of the six fractions of interest: RNPs, 40S, 60S+80S, low polysomes, medium polysomes and heavy polysomes. RNA was extraced from these fractions, follwing proteinase K treatment, by hot acid phenol method. In case of unfractionated lysates, RNA was extracted using TRIzol (Invitrogen) according to manufacturerM-bM-^@M-^Ys instructions. mRNA-seq samples were prepared from 1 M-NM-<g of total RNA (in case of sucrose gradient fractions and unfractionated lysates) and subject to Illumina based sequencing. Puromycin-treated lysates of mature oocytes or 0-2h Drosophila activated eggs (containing ~540 M-NM-<g of total RNA) were also subjected to separation by velocity sedimentation through sucrose gradients. Puromycin causes premature termination of elongating ribosomes and thus it can be used to determine whether the mRNAs co-sedimenting with the polysomal peaks (defined here as M-bM-^IM-%5 ribosomes) were actively engaged in translation. As an independent approach to assess translation and obtain information on the position of ribosomes on mRNAs, we employed ribosome footprinting. In addition to analyzing the same samples, as by polysome profiling, we also analyzed png mutant activated eggs by ribosome footprinting. Ribosome footprint profiling measures the number of ribosome-protected fragments (RPFs) derived from the mRNAs of each gene, resulting in a singular value of translational efficiency (TE) for each gene (TE=RPF/RNA).
2014-06-12 | E-GEOD-52799 | biostudies-arrayexpress
Project description:Emerging evidence indicates that heterogeneity in ribosome composition can give rise to specialized functions. Until now, research mainly focused on differences in core ribosomal proteins and associated factors. The impact of posttranslational modifications has not yet been studied systematically. Analyzing ribosome heterogeneity is challenging since individual proteins can be part of different subcomplexes (40S, 60S, 80S and polysomes). Here, we develop polysome proteome profiling to obtain unbiased proteomic maps across ribosomal subcomplexes. Our method combines extensive fractionation by sucrose gradient centrifugation with quantitative mass spectrometry. The high resolution of the profiles allows us to assign proteins to specific subcomplexes. Phosphoproteomics on the fractions reveals that phosphorylation of serine 38 in RPL12/uL11 -- a known mitotic CDK1 substrate -- is strongly depleted in polysomes. Follow-up experiments confirm that RPL12/uL11 phosphorylation regulates translation of specific subsets of mRNAs during mitosis. Together, our results show that posttranslational modification of ribosomal proteins can regulate translation.
2019-05-03 | GSE112186 | GEO
Project description:Emerging evidence indicates that heterogeneity in ribosome composition can give rise to specialized functions. Until now, research mainly focused on differences in core ribosomal proteins and associated factors. The impact of posttranslational modifications has not yet been studied systematically. Analyzing ribosome heterogeneity is challenging since individual proteins can be part of different subcomplexes (40S, 60S, 80S and polysomes). Here, we develop polysome proteome profiling to obtain unbiased proteomic maps across ribosomal subcomplexes. Our method combines extensive fractionation by sucrose gradient centrifugation with quantitative mass spectrometry. The high resolution of the profiles allows us to assign proteins to specific subcomplexes. Phosphoproteomics on the fractions reveals that phosphorylation of serine 38 in RPL12/uL11 -- a known mitotic CDK1 substrate -- is strongly depleted in polysomes. Follow-up experiments confirm that RPL12/uL11 phosphorylation regulates translation of specific subsets of mRNAs during mitosis. Together, our results show that posttranslational modification of ribosomal proteins can regulate translation.
2019-05-03 | GSE112185 | GEO
Project description:Emerging evidence indicates that heterogeneity in ribosome composition can give rise to specialized functions. Until now, research mainly focused on differences in core ribosomal proteins and associated factors. The impact of posttranslational modifications has not yet been studied systematically. Analyzing ribosome heterogeneity is challenging since individual proteins can be part of different subcomplexes (40S, 60S, 80S and polysomes). Here, we develop polysome proteome profiling to obtain unbiased proteomic maps across ribosomal subcomplexes. Our method combines extensive fractionation by sucrose gradient centrifugation with quantitative mass spectrometry. The high resolution of the profiles allows us to assign proteins to specific subcomplexes. Phosphoproteomics on the fractions reveals that phosphorylation of serine 38 in RPL12/uL11 -- a known mitotic CDK1 substrate -- is strongly depleted in polysomes. Follow-up experiments confirm that RPL12/uL11 phosphorylation regulates translation of specific subsets of mRNAs during mitosis. Together, our results show that posttranslational modification of ribosomal proteins can regulate translation.
2019-05-03 | GSE112183 | GEO
Project description:Cotranslational targeting into the endoplasmic reticulum (ER) by the Signal Recognition Particle (SRP) is a key event determining polypeptide fate in eukaryotic cells. Here, we globally define the principles and mechanisms of SRP binding and ER targeting in vivo. Cotranslational targeting through SRP is the dominant route into the ER for all secretory proteins, regardless of targeting signal characteristics. Cytosolic SRP functions in a pioneer translation round that builds a membrane-resident mRNAs pool, explaining how low SRP levels suffice for the secretory load. SRP does not induce an elongation arrest; consequently, kinetic competition between targeting and translation elongation dictates which substrates are translocated post-translationally. Unexpectedly, SRP binds most secretory ribosomal complexes before targeting signals are synthesized. We show non-coding mRNA elements can promote signal-independent SRP pre-recruitment. Our study defines the complex kinetic interplay between elongation and determinants in the polypeptide and mRNA modulating SRP-substrate selection and membrane targeting in vivo. Ribosome profiling (RiboSeq) and RNA-seq of subcellular fractions of ribosomes. Soluble and membrane bound ribosomes are separated by centrifugation, and SRP-bound ribosomes are immunoprecipitated from the soluble fraction. Polysomes and monosomes are separated by sucrose gradient ultracentrifugation.
2016-08-03 | E-GEOD-74393 | biostudies-arrayexpress
Project description:Ribosome assembly occurs mainly in the nucleolus yet recent studies have revealed robust enrichment and translation of mRNAs encoding many ribosomal proteins (RPs) in axons, far away from neuronal cell bodies. Here, we report a physical and functional interaction between locally synthesized RPs and ribosomes in the axon. We show that axonal RP translation is regulated through a novel sequence motif, CUIC, that forms an RNA-loop structure in the region immediately upstream of the initiation codon. Using imaging and subcellular proteomics techniques, we show that RPs synthesized in axons join axonal ribosomes in a nucleolus-independent fashion. Inhibition of axonal CUIC-regulated RP translation causes a significant decline in local translation activity and markedly reduces axon branching in the brain, revealing the physiological relevance of axonal RP synthesis in vivo. These results suggest that axonal translation supplies cytoplasmic RPs to maintain/modify local ribosomal function far from the nucleolus in neurons.
2019-12-11 | GSE135502 | GEO
Project description:eIF3 is a multi-subunit complex thought to execute numerous functions in canonical translation initiation, including mRNA recruitment to the 40S ribosome, scanning for the start codon, and inhibition of 60S subunit joining 1–3. eIF3 was also found to interact with 40S and 60S ribosomal proteins and translation elongation factors 4, but a direct involvement in translation elongation has never been demonstrated. Using selective ribosome profiling, we made the unexpected observation that eIF3 remains bound to post-initiation 80S ribosomes, followed by release after translation of ~50 codons. Furthermore, eIF3 deficiency reduces early ribosomal elongation speed, particularly on mRNAs encoding proteins associated with membrane-associated functions, resulting in defective synthesis of their encoded proteins and abnormal mitochondrial and lysosomal physiology. Accordingly, heterozygous eIF3e+/- knockout mice accumulate giant mitochondria in skeletal muscle and show a progressive decline in muscle strength with age. Hence, in addition to its canonical role in translation initiation, eIF3 interacts with 80S ribosomes to enhance, at the level of early elongation, the synthesis of proteins with membrane-associated functions, an activity that is critical for normal muscle health.
2020-06-15 | GSE149697 | GEO