HNRNPU facilitates antibody class-switch recombination through C-NHEJ promotion and R-loop suppression

Autor: Ahmed M. Refaat, Mikiyo Nakata, Afzal Husain, Hidetaka Kosako, Tasuku Honjo, Nasim A. Begum
Jazyk: angličtina
Rok vydání: 2023
Předmět:
Zdroj: Cell Reports, Vol 42, Iss 3, Pp 112284- (2023)
Druh dokumentu: article
ISSN: 2211-1247
DOI: 10.1016/j.celrep.2023.112284
Popis: Summary: B cells generate functionally different classes of antibodies through class-switch recombination (CSR), which requires classical non-homologous end joining (C-NHEJ) to join the DNA breaks at the donor and acceptor switch (S) regions. We show that the RNA-binding protein HNRNPU promotes C-NHEJ-mediated S-S joining through the 53BP1-shieldin DNA-repair complex. Notably, HNRNPU binds to the S region RNA/DNA G-quadruplexes, contributing to regulating R-loop and single-stranded DNA (ssDNA) accumulation. HNRNPU is an intrinsically disordered protein that interacts with both C-NHEJ and R-loop complexes in an RNA-dependent manner. Strikingly, recruitment of HNRNPU and the C-NHEJ factors is highly sensitive to liquid-liquid phase separation inhibitors, suggestive of DNA-repair condensate formation. We propose that HNRNPU facilitates CSR by forming and stabilizing the C-NHEJ ribonucleoprotein complex and preventing excessive R-loop accumulation, which otherwise would cause persistent DNA breaks and aberrant DNA repair, leading to genomic instability.
Databáze: Directory of Open Access Journals