Using mitoribosomal profiling to investigate human mitochondrial translation
Ontology highlight
ABSTRACT:
PROVIDER: PRJEB23692 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| ERR2208504.fastq.gz | Fastqsanger.gz | |||
| ERR2208505.fastq.gz | Fastqsanger.gz | |||
| ERR2208506.fastq.gz | Fastqsanger.gz | |||
| ERR2208507.fastq.gz | Fastqsanger.gz | |||
| ERR2208508.fastq.gz | Fastqsanger.gz |
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Project description:Background: Gene expression in human mitochondria has various idiosyncratic features. One of these was recently revealed as the unprecedented recruitment of a mitochondrially-encoded tRNA as a structural component of the large mitoribosomal subunit. In porcine particles this is mt-tRNA Phe whilst in humans it is mt-tRNA Val. We have previously shown that when a mutation in mt-tRNA Val causes very low steady state levels, there is preferential recruitment of mt-tRNA Phe. We have investigated whether this altered mitoribosome affects intra-organellar protein synthesis. Methods: By using mitoribosomal profiling we have revealed aspects of mitoribosome behaviour with its template mt-mRNA under both normal conditions as well as those where the mitoribosome has incorporated mt-tRNA Phe. Results: Analysis of the mitoribosome residency on transcripts under control conditions reveals that although mitochondria employ only 22 mt-tRNAs for protein synthesis, the use of non-canonical wobble base pairs at codon position 3 does not cause any measurable difference in mitoribosome occupancy irrespective of the codon. Comparison of the profile of aberrant mt-tRNA Phe containing mitoribosomes with those of controls that integrate mt-tRNA Val revealed that the impaired translation seen in the latter was not due to stalling on triplets encoding either of these amino acids. The alterations in mitoribosome interactions with start codons was not directly attributable to the either the use of non-cognate initiation codons or the presence or absence of 5' leader sequences, except in the two bicistronic RNA units, RNA7 and RNA14 where the initiation sites are internal. Conclusions: These data report the power of mitoribosomal profiling in helping to understand the subtleties of mammalian mitochondrial protein synthesis. Analysis of profiles from the mutant mt-tRNA Val cell line suggest that despite mt-tRNA Phe being preferred in the porcine mitoribosome, its integration into the human counterpart results in a suboptimal structure that modifies its interaction with mt-mRNAs.
| S-EPMC5771143 | biostudies-literature
Project description:Human 143B.206 Rho+ cells (depleted mitochondrial DNA) and cytoplasts (derived from mitochondrial patient fibroblast containing C1624T mutation in mitochondrial tRNAVal ) were previously used to generated transmitochondrial cybrid lines. Hek293T cells,143B cells and cybrid cells were cultured in DMEM supplemented with 10% FCS in 5% CO2 at 37 °C. Cells were treated with Chloramphenicol (100 μg/ ml) for 15 min before harvest. Cells were then lysed and RNase I digested. Lysates were then loaded on a sucrose gradient (7%-47%). Fractions containing mito-monosomes were used to isolated RNA which were used to generate the library for deep sequencing. Mitoribosomal profiling were generated for both control (143B and Hek293T) and cybrid cells to reveal aspects of mitoribosome behaviour.
2017-12-01 | E-MTAB-6284 | biostudies-arrayexpress
Project description:Using ribosome profiling to investigate the effect of p53 on translation in cancer cells
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Project description:The synthesis of mitochondrial OXPHOS complexes is central to cellular metabolism, yet many molecular details of mitochondrial translation remain elusive. It is commonly held view that translation initiation in human mitochondria proceeded in a manner similar to bacterial systems, with the mitoribosomal small subunit bound to the initiation factors, mtIF2 and mtIF3, along with initiator tRNA and an mRNA. However, unlike in bacteria, most human mitochondrial mRNAs lack 5′ leader sequences that can mediate small subunit binding, raising the question of how leaderless mRNAs are recognized by mitoribosomes. By using novel in vitro mitochondrial translation initiation assays, alongside biochemical and genetic characterization of cellular knockouts of mitochondrial translation factors, we describe unique features of translation initiation in human mitochondria. We show that in vitro, leaderless mRNA transcripts can be loaded directly onto assembled 55S mitoribosomes, but not onto the mitoribosomal small subunit (28S). In addition, we demonstrate that while mtIF2 is indispensable for mitochondrial translation, mtIF3 activity is not required for translation of leaderless mitochondrial transcripts but is essential for translation of ATP6 in the case of the bicistronic ATP8/ATP6 transcript. Our results confirm important evolutionary divergences of the mitochondrial translation system, and further our understanding of a process central to eukaryotic metabolism.
2022-12-01 | GSE156937 | GEO
Project description:Haplo-insufficiency profiling followed by Gene-set enrichment analysis of sensitive strains was conducted in yeast treated with tigecycline. This revealed significant enrichment of genes involved in mitochondrial translation, similar to that seen with the known mitochondrial translation inhibitors chloramphenicol and linezolid
2011-11-01 | E-MTAB-814 | biostudies-arrayexpress
Project description:MicroRNAs are well known to mediate translational repression and mRNA degradation in the cytoplasm. Various microRNAs have also been detected in membrane-compartmentalized organelles, but the functional significance has remained elusive. Here we report that miR-1, a microRNA specifically induced during myogenesis, efficiently enters the mitochondria where it unexpectedly stimulates, rather than represses, the translation of specific mitochondrial genome-encoded transcripts. We show that this positive effect requires specific miR:mRNA base-pairing and Ago2, but not its functional partner GW182, which is excluded from the mitochondria. We provide evidence for the direct action of Ago2 in mitochondrial translation by Ago2 CrossLinking ImmunoPrecipitation coupled with sequencing (CLIP-seq), functional rescue with mitochondria-targeted Ago2, and selective inhibition of the microRNA machinery in the cytoplasm. These findings unveil a positive function of microRNA in mitochondrial translation and suggest a highly coordinated myogenic program via miR-1 mediated translational stimulation in the mitochondria and repression in the cytoplasm. Examination of miRNA's regulation function in mitochondria in C2C12 myoblasts cells and myotubes cells with CLIP-seq (Ago2).
2014-08-01 | E-GEOD-57596 | biostudies-arrayexpress
Project description:The mitochondrial matrix is unique in that it must integrate folding and assembly of proteins derived from nuclear and mitochondrial genomes. In C. elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial matrix-localized ornithine trans-carbamylase (OTC) induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here, we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response involved widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing due to transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3. This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt. triplicate experiment of 3 conditions (untreated, GTPP treatment, CDDO treatment)
2016-06-28 | E-GEOD-75247 | biostudies-arrayexpress
Project description:The mitochondrial matrix is unique in that it must integrate folding and assembly of proteins derived from nuclear and mitochondrial genomes. In C. elegans, the mitochondrial unfolded protein response (UPRmt) senses matrix protein misfolding and induces a program of nuclear gene expression, including mitochondrial chaperonins, to promote mitochondrial proteostasis. While misfolded mitochondrial matrix-localized ornithine trans-carbamylase (OTC) induces chaperonin expression, our understanding of mammalian UPRmt is rudimentary, reflecting a lack of acute triggers for UPRmt activation. This limitation has prevented analysis of the cellular responses to matrix protein misfolding and the effects of UPRmt on mitochondrial translation to control protein folding loads. Here, we combine pharmacological inhibitors of matrix-localized HSP90/TRAP1 or LON protease, which promote chaperonin expression, with global transcriptional and proteomic analysis to reveal an extensive and acute response of human cells to UPRmt. This response involved widespread induction of nuclear genes, including matrix-localized proteins involved in folding, pre-RNA processing and translation. Functional studies revealed rapid but reversible translation inhibition in mitochondria occurring concurrently with defects in pre-RNA processing due to transcriptional repression and LON-dependent turnover of the mitochondrial pre-RNA processing nuclease MRPP3. This study reveals that acute mitochondrial protein folding stress activates both increased chaperone availability within the matrix and reduced matrix-localized protein synthesis through translational inhibition, and provides a framework for further dissection of mammalian UPRmt. triplicate experiment of 2 conditions (untreated, GTPP treatment)
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Project description:We developed a simple method that combined biochemical mitochondria isolation and pulse SILAC approach to monitor the mitochondrial translation. Our approach allows us to quantify 12 out of the 13 mitochondrial translation products, the highest coverage among analogous methods reported, and provide a global picture of (post-)translational regulation in mitochondria. Replicate 1: H-CRP_M-DMSO, Replicate 2: M-CRP_H-DMSO.
2022-12-28 | PXD022476 | JPOST Repository