Nature Communications (Apr 2024)

Accelerated DNA replication fork speed due to loss of R-loops in myelodysplastic syndromes with SF3B1 mutation

  • David Rombaut,
  • Carine Lefèvre,
  • Tony Rached,
  • Sabrina Bondu,
  • Anne Letessier,
  • Raphael M. Mangione,
  • Batoul Farhat,
  • Auriane Lesieur-Pasquier,
  • Daisy Castillo-Guzman,
  • Ismael Boussaid,
  • Chloé Friedrich,
  • Aurore Tourville,
  • Magali De Carvalho,
  • Françoise Levavasseur,
  • Marjorie Leduc,
  • Morgane Le Gall,
  • Sarah Battault,
  • Marie Temple,
  • Alexandre Houy,
  • Didier Bouscary,
  • Lise Willems,
  • Sophie Park,
  • Sophie Raynaud,
  • Thomas Cluzeau,
  • Emmanuelle Clappier,
  • Pierre Fenaux,
  • Lionel Adès,
  • Raphael Margueron,
  • Michel Wassef,
  • Samar Alsafadi,
  • Nicolas Chapuis,
  • Olivier Kosmider,
  • Eric Solary,
  • Angelos Constantinou,
  • Marc-Henri Stern,
  • Nathalie Droin,
  • Benoit Palancade,
  • Benoit Miotto,
  • Frédéric Chédin,
  • Michaela Fontenay

DOI
https://doi.org/10.1038/s41467-024-46547-7
Journal volume & issue
Vol. 15, no. 1
pp. 1 – 20

Abstract

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Abstract Myelodysplastic syndromes (MDS) with mutated SF3B1 gene present features including a favourable outcome distinct from MDS with mutations in other splicing factor genes SRSF2 or U2AF1. Molecular bases of these divergences are poorly understood. Here we find that SF3B1-mutated MDS show reduced R-loop formation predominating in gene bodies associated with intron retention reduction, not found in U2AF1- or SRSF2-mutated MDS. Compared to erythroblasts from SRSF2- or U2AF1-mutated patients, SF3B1-mutated erythroblasts exhibit augmented DNA synthesis, accelerated replication forks, and single-stranded DNA exposure upon differentiation. Importantly, histone deacetylase inhibition using vorinostat restores R-loop formation, slows down DNA replication forks and improves SF3B1-mutated erythroblast differentiation. In conclusion, loss of R-loops with associated DNA replication stress represents a hallmark of SF3B1-mutated MDS ineffective erythropoiesis, which could be used as a therapeutic target.