en
Scientific article
English

Phase-separated ribosome-nascent chain complexes in genotoxic stress response

Published inRNA, vol. 29, no. 10, p. 1557-1574
Publication date2023-10
First online date2023-07-17
Abstract

Assemblysomes are EDTA- and RNase-resistant ribonucleoprotein (RNP) complexes of paused ribosomes with protruding nascent polypeptide chains. They have been described in yeast and human cells for the proteasome subunit Rpt1, and the disordered amino-terminal part of the nascent chain was found to be indispensable for the accumulation of the Rpt1-RNP into assemblysomes. Motivated by this, to find other assemblysome-associated RNPs we used bioinformatics to rank subunits of Saccharomyces cerevisiae protein complexes according to their amino-terminal disorder propensity. The results revealed that gene products involved in DNA repair are enriched among the top candidates. The Sgs1 DNA helicase was chosen for experimental validation. We found that indeed nascent chains of Sgs1 form EDTA-resistant RNP condensates, assemblysomes by definition. Moreover, upon exposure to UV, SGS1 mRNA shifted from assemblysomes to polysomes, suggesting that external stimuli are regulators of assemblysome dynamics. We extended our studies to human cell lines. The BLM helicase, ortholog of yeast Sgs1, was identified upon sequencing assemblysome-associated RNAs from the MCF7 human breast cancer cell line, and mRNAs encoding DNA repair proteins were overall enriched. Using the radiation-resistant A549 cell line, we observed by transmission electron microscopy that 1,6-hexanediol, an agent known to disrupt phase-separated condensates, depletes ring ribosome structures compatible with assemblysomes from the cytoplasm of cells and makes the cells more sensitive to X-ray treatment. Taken together, these findings suggest that assemblysomes may be a component of the DNA damage response from yeast to human.

eng
Keywords
  • BLM
  • DNA damage response
  • Sgs1
  • Assemblysomes
  • Phase separation
  • Humans
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae / metabolism
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • RecQ Helicases / genetics
  • Edetic Acid / metabolism
  • DNA Damage
  • RNA / metabolism
  • Ribonucleoproteins / genetics
  • Ribosomes / genetics
  • Ribosomes / metabolism
Citation (ISO format)
NÉMETH-SZATMÁRI, Orsolya et al. Phase-separated ribosome-nascent chain complexes in genotoxic stress response. In: RNA, 2023, vol. 29, n° 10, p. 1557–1574. doi: 10.1261/rna.079755.123
Main files (1)
Article (Published version)
accessLevelRestrictedaccessLevelPublic 10/01/2024
Secondary files (13)
Identifiers
ISSN of the journal1355-8382
132views
0downloads

Technical informations

Creation11/09/2023 1:50:25 PM
First validation11/09/2023 2:14:27 PM
Update time11/09/2023 2:14:27 PM
Status update11/09/2023 2:14:27 PM
Last indexation02/01/2024 10:59:12 AM
All rights reserved by Archive ouverte UNIGE and the University of GenevaunigeBlack