The ribosome is a complex macromolecular machine and serves as an ideal system for understanding biological macromolecular assembly. Direct observation of ribosome assembly in vivo is difficult, as few intermediates have been isolated and thoroughly characterized. Herein, we deploy a genetic system to starve cells of an essential ribosomal protein, which results in the accumulation of assembly intermediates that are competent for maturation. Quantitative mass spectrometry and single-particle cryo-electron microscopy reveal 13 distinct intermediates, which were each resolved to ∼4-5 Å resolution and could be placed in an assembly pathway. We find that ribosome biogenesis is a parallel process, that blocks of structured rRNA and proteins assemble cooperatively, and that the entire process is dynamic and can be "re-routed" through different pathways as needed. This work reveals the complex landscape of ribosome assembly in vivo and provides the requisite tools to characterize additional assembly pathways for ribosomes and other macromolecular machines.
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http://dx.doi.org/10.1016/j.cell.2016.11.020 | DOI Listing |
Ribosome biogenesis is pivotal in the self-replication of life. In Escherichia coli, three ribosomal RNAs and 54 ribosomal proteins are synthesized and subjected to cooperative hierarchical assembly facilitated by numerous accessory factors. Realizing ribosome biogenesis in vitro is a critical milestone for understanding the self-replication of life and creating artificial cells.
View Article and Find Full Text PDFFood Res Int
January 2025
School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, China. Electronic address:
Intestinal microbiota could respond to dietary fibres that are fermented by the gut microbiota, like prebiotics. Nevertheless, the dynamics of intestinal microbial community longitudinally after prebiotics intake, are still largely unknown. The current study unrevealed the successional process of intestinal microbial community after inulin supplementation, and the effect of supplementation dosage thereof, based on analysis of 16S rRNA gene sequences in C57BL/6 mice.
View Article and Find Full Text PDFGenes (Basel)
December 2024
Laboratório de Estudos Cromossômicos, Instituto de Biologia, Universidade de Campinas, Campinas 13083-862, SP, Brazil.
Background: The satellite DNA (satDNA) PcP190 has been identified in multiple frog species from seven phylogenetically distant families within Hyloidea, indicating its broad distribution. This satDNA consists of repeats of approximately 190 bp and exhibits a highly conserved region (CR) of 120 bp, which is similar to the transcribed region of 5S ribosomal DNA (rDNA), and a hypervariable region (HR) that varies in size and nucleotide composition among and within species. Here, to improve our understanding of PcP190 satDNA, we searched for evidence of its transcription in the available transcriptomes of (Bufonidae) and (Leptodactylidae), two phylogenetically distantly related species.
View Article and Find Full Text PDFUnlabelled: Eastern equine encephalitis virus (EEEV) is an arthropod-borne, positive-sense RNA alphavirus posing a substantial threat to public health. Unlike similar viruses such as SARS-CoV-2, EEEV replicates efficiently in neurons, producing progeny viral particles as soon as 3-4 hours post-infection. EEEV infection, which can cause severe encephalitis with a human mortality rate surpassing 30%, has no licensed, targeted therapies, leaving patients to rely on supportive care.
View Article and Find Full Text PDFJ Cell Biol
February 2025
Cecil H. and Ida Green Center for Reproductive Biology Sciences, University of Texas Southwestern Medical Center, Dallas, TX, USA.
Mono(ADP-ribosyl)ation (MARylation) is emerging as a critical regulator of ribosome function and translation. Herein, we demonstrate that RACK1, an integral component of the ribosome, is MARylated by the mono(ADP-ribosyl) transferase (MART) PARP14 in ovarian cancer cells. MARylation of RACK1 is required for stress granule formation and promotes the colocalization of RACK1 in stress granules with G3BP1, eIF3η, and 40S ribosomal proteins.
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