Ribosome Biogenesis and Protein Synthesis Mechanisms

Ribosome biogenesis is a conserved, energy-intensive pathway that assembles ribosomal RNA (rRNA) and ribosomal proteins into functional small (40S) and large (60S) subunits. In eukaryotes, synthesis begins in the nucleolus with transcription of a 47S pre-rRNA by RNA polymerase I, followed by sequential cleavage, chemical modification and folding of the rRNA, aided by small nucleolar RNPs and assembly factors. Ribosomal proteins are synthesised in the cytoplasm, imported into the nucleus and integrated with pre-rRNAs. Mature subunits are exported to the cytoplasm where they engage in translation initiation, elongation and termination, directed by translation factors and GTPases. Quality control pathways monitor assembly defects and translational stalls, triggering ribosome-associated quality control (RQC) and ubiquitin-dependent degradation when necessary. Dysregulation of biogenesis or translation underlies developmental disorders, cancer and stress responses, highlighting the therapeutic potential of targeting ribosome assembly and function.

Research from Nature Portfolio

A novel RNA-centric method has been introduced to map protein–rRNA interactions in living cells with unprecedented region specificity. By selectively targeting RNase H to defined rRNA sequences, this approach uncovered previously unknown factors that bind 45S pre-rRNA and regulate early subunit assembly and rRNA processing. The technique offers a blueprint for dissecting the dynamic interactome of pre-ribosomal particles under physiological conditions.

The chemotherapeutic agent CX-5461, developed to inhibit RNA polymerase I and rRNA synthesis, has been shown to induce extensive collateral mutagenesis in addition to synthetic lethality in BRCA-deficient cells. These findings prompt a re-evaluation of ribosome-targeted therapies, balancing antitumour efficacy with potential genotoxic side effects and suggesting new risk–benefit parameters for clinical applications.

A foundational study has delineated how stalled ribosomes are ubiquitinated on specific 40S proteins by a dedicated E3 ligase, marking them for subunit dissociation and nascent chain degradation. High-resolution structures revealed that ribosome collisions create a unique interface recognised by the ligase, thus defining the molecular trigger for RQC and offering targets for modulating translational fidelity.

Ribosome Biogenesis and Protein Synthesis Mechanisms publication trend

The graph below shows the total number of articles in ribosome biogenesis and protein synthesis mechanisms across all publications each year (not limited to Nature Index journals).

Technical terms

Ribosome biogenesis: Multistep assembly of rRNA and ribosomal proteins into mature ribosomal subunits within the nucleus and cytoplasm.

Pre-rRNA processing: Sequential cleavage and chemical modification of precursor rRNA transcripts to generate mature 18S, 5.8S and 28S rRNAs.

Ribosomal collision: Encounter of a trailing ribosome with a stalled leading ribosome, triggering quality control pathways.

Ribosome-associated quality control (RQC): Cellular mechanism that recognises stalled ribosomes and targets aberrant nascent chains for ubiquitin-mediated degradation.

Ubiquitination: Covalent attachment of ubiquitin to target proteins, marking them for proteasomal degradation or modulating their function.

Ribotoxic stress response (RSR): Signalling cascade initiated by ribosome damage or collision, determining cell fate decisions such as repair or apoptosis.

References

1. Ribosome biogenesis in disease: new players and therapeutic targets. Signal Transduction and Targeted Therapy (2023).
2. The ribotoxic stress response drives UV-mediated cell death. Cell (2024).
3. TREX reveals proteins that bind to specific RNA regions in living cells. Nature Methods (2024).
4. The chemotherapeutic drug CX-5461 is a potent mutagen in cultured human cells. Nature Genetics (2023).
5. ZNF598 Is a Quality Control Sensor of Collided Ribosomes. Molecular Cell (2018).