A late-stage assembly checkpoint of the human mitochondrial ribosome large subunit
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PROVIDER: PRJNA742116 | ENA |
REPOSITORIES: ENA
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Project description:The epitranscriptome plays a key regulatory role in cellular processes in health and disease, including ribosome biogenesis. Here, analysis of the human mitochondrial transcriptome shows that 2’-O-methylation is limited to residues of the mitoribosomal large subunit (mtLSU) 16S mt-rRNA, modified by MRM1, MRM2, and MRM3. Ablation of MRM2 leads to a severe impairment of the oxidative phosphorylation system, caused by defective mitochondrial translation and accumulation of mtLSU assembly intermediates. Structures of these particles (2.58Å) present disordered RNA domains, partial occupancy of bL36m and bound MALSU1:L0R8F8:mtACP anti-association module. Additionally, we present five mtLSU assembly states with different intersubunit interface configurations. Complementation studies demonstrate that the methyltransferase activity of MRM2 is dispensable for mitoribosome biogenesis. The Drosophila melanogaster orthologue, DmMRM2, is an essential gene, with its knock-down leading to developmental arrest. This work identifies a key late-stage quality control step during mtLSU assembly, ultimately contributing to the maintenance of mitochondrial homeostasis.
2021-12-19 | GSE179085 | GEO
Project description:Human mitoribosomes are macromolecular complexes essential for translation of 11 mitochondrial mRNAs. The large and the small mitoribosomal subunits undergo a multistep maturation process that requires the involvement of several factors. Among these factors, GTP-binding proteins (GTPBPs) play an important role as GTP hydrolysis can provide energy throughout the assembly stages. In bacteria, many GTPBPs are needed for the maturation of ribosome subunits and, of particular interest for this study, ObgE has been shown to assist in the 50S subunit assembly. Here, we characterize the role of a related human Obg-family member, GTPBP5. We show that GTPBP5 interacts specifically with the large mitoribosomal subunit (mt-LSU) proteins and several late-stage mitoribosome assembly factors, including NSUN4-MTERF4 complex, MRM2 methyltransferase, MALSU1 and MTG1. Interestingly, we find that interaction of GTPBP5 with the mt-LSU is compromised in the presence of a non-hydrolyzable analog of GTP, suggesting a different mechanism of action of this protein in contrast to that of other Obg-family GTPBPs. CRISPR/Cas9-mediated GTPBP5 ablation leads to severe impairment in the oxidative phosphorylation system, concurrent with a decrease in mitochondrial translation, reduced monosome formation and elevated levels of certain mitoribosome assembly factors. Overall, our data indicate an important role of GTPBP5 in mitochondrial function and suggest its involvement in the late-stage maturation of the mt-LSU maturation.
2020-11-09 | PXD017384 | Pride
Project description:Protein production by the ribosomes is fundamental to life and proper assembly of the ribosome is required for protein production. The RNA, which is post-transcriptionally modified, provides the platform for ribosome assembly. Thus, a complete understanding of ribosome assembly requires the determination of the RNA post-transcriptional modifications in all the ribosome assembly intermediates and on each pathway. There are 26 RNA post-transcriptional modifications in 23S RNA of the mature Escherichia coli (E.coli) large ribosomal subunit. The levels of these modifications have been investigated extensively only for a small number of large subunit intermediates and under a limited number of cellular and environmental conditions. In this study we determine the level of incorporations of 2-methyl adenosine, 3-methyl pseudouridine, 5-hydroxycytosine and eight pseudouridines in an early-stage E.coli large subunit assembly intermediate with a sedimentation coefficient of 27S. The 27S intermediate is one of three large subunit intermediates accumulated in E.coli cells lacking the DEAD-box RNA helicase DbpA and expressing the helicase inactive R331A DbpA construct. The majority of the investigated modifications are incorporated into the 27S large subunit intermediate to similar levels as in the mature 50S large subunit, indicating that these early modifications or the enzymes that incorporate them have important roles in the initial events of large subunit ribosome assembly.
2024-05-15 | GSE232539 | GEO
Project description:To investigate the distribution of ribosomes in late-stage oocyte to infer their translational status.
2022-12-31 | GSE210503 | GEO
Project description:eEF3 promotes late stages of tRNA translocation on the ribosome
| PRJNA672335 | ENA
Project description:Yeast large ribosomal subunit (LSU) precursors are subject to substantial changes in protein composition during their maturation due to coordinated transient interactions with a large number of ribosome biogenesis factors and due to the assembly of ribosomal proteins. These compositional changes go along with stepwise processing of LSU rRNA precursors and with specific rRNA folding events, as revealed by recent cryo-electron microscopy analyses of late nuclear and cytoplasmic LSU precursors. Here we aimed to analyze changes in the spatial rRNA surrounding of selected ribosomal proteins during yeast LSU maturation. For this we combined a recently developed tethered tertiary structure probing approach with both targeted and high-throughput readout strategies. Several structural features of late LSU precursors were faithfully detected by this procedure. In addition, the obtained data let us suggest that early rRNA precursor processing events are accompanied by a global transition from a flexible to a spatially restricted rRNA conformation. For intermediate LSU precursors, a number of structural hallmarks could be addressed which include the fold of the internal transcribed spacer between 5.8S rRNA and 25S rRNA, the orientation of the central protuberance and the spatial organization of the interface between LSU rRNA domains I and III.
2017-04-01 | GSE97276 | GEO
Project description:Ribosomes must be formed quickly (to support cellular growth demands) and accurately (to ensure proper translation of the genetic code). The assembly of ribosomes in vivo requires not only the constituent rRNAs and ribosomal proteins (r-proteins), but also assembly factors. Several of these factors are GTPases. However, the molecular role that these GTPases play is not understood. Hypotheses range from serving a regulatory/checkpoint role to serving a direct mechanical role in structural rearrangements (such as serving as an RNA chaperone). The objective of our research is to identify the precise function of one of these essential GTPases in the assembly of the 50S subunit and provide a clear picture for the molecular rearrangements associated with its function. This essential GTPase from Bacillus subtilis, the model organism for Gram-positive bacteria, is RbgA, which constitute a key player in the late maturation steps of the 50S ribosome subunit.
2022-01-27 | PXD023644 | Pride
Project description: Not available
| S-EPMC7797037 | biostudies-literature
Project description:NOL12 5'-3' exoribonucleases, conserved among eukaryotes, play important roles in pre-rRNA processing, ribosome assembly and export. The most well-described yeast counterpart, Rrp17, is required for maturation of 5.8 and 25S rRNAs, whereas human hNOL12 is crucial for the separation of the large (LSU) and small (SSU) ribosome subunit rRNA precursors. In this study we demonstrate that plant AtNOL12 is also involved in rRNA biogenesis, specifically in the processing of the LSU rRNA precursor, 27S pre-rRNA. Importantly, the absence of AtNOL12 alters the expression of many ribosomal protein and ribosome biogenesis genes. These changes could potentially exacerbate rRNA biogenesis defects, or, conversely, they might stem from the disturbed ribosome assembly caused by delayed pre-rRNA processing. Moreover, exposure of the nol12 mutant to stress factors, including heat and pathogen Pseudomonas syringae, enhances the observed molecular phenotypes, linking pre-rRNA processing to stress response pathways. The aberrant rRNA processing, dependent on AtNOL12, could impact ribosome function, as suggested by improved mutant resistance to ribosome-targeting antibiotics. Despite extensive studies, the pre-rRNA processing pathway in plants remains insufficiently characterized. Our investigation reveals the involvement of AtNOL12 in the maturation of rRNA precursors, correlating this process to stress response in Arabidopsis. These findings contribute to a more comprehensive understanding of plant ribosome biogenesis.
2023-11-07 | GSE232067 | GEO
Project description: Not available
| S-EPMC3020115 | biostudies-literature