RNF4 and USP7 cooperate in ubiquitin-regulated steps of DNA replication

Ya-Chu Chang, Kevin J Lin, Ryan M. Baxley, Wesley Durrett, Liangjun Wang, Olivera Stojkova, Maximilian Billmann, Henry N Ward, Chad L. Myers, Anja K Bielinsky

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


DNA replication requires precise regulation achieved through post-translational modifications, including ubiquitination and SUMOylation. These modifications are linked by the SUMO-targeted E3 ubiquitin ligases (STUbLs). Ring finger protein 4 (RNF4), one of only two mammalian STUbLs, participates in double-strand break repair and resolving DNA-protein cross-links. However, its role in DNA replication has been poorly understood. Using CRISPR/Cas9 genetic screens, we discovered an unexpected dependency of RNF4 mutants on ubiquitin specific peptidase 7 (USP7) for survival in TP53-null retinal pigment epithelial cells. TP53 -/- /RNF4 -/- /USP7 -/- triple knockout (TKO) cells displayed defects in DNA replication that cause genomic instability. These defects were exacerbated by the proteasome inhibitor bortezomib, which limited the nuclear ubiquitin pool. A shortage of free ubiquitin suppressed the ataxia telangiectasia and Rad3-related (ATR)-mediated checkpoint response, leading to increased cell death. In conclusion, RNF4 and USP7 work cooperatively to sustain a functional level of nuclear ubiquitin to maintain the integrity of the genome.

Original languageEnglish (US)
Article number230068
JournalOpen biology
Issue number8
StatePublished - Aug 23 2023

Bibliographical note

Publisher Copyright:
© 2023 The Authors.


  • RNF4
  • STUbL
  • SUMO
  • USP7
  • genome stability
  • ubiquitin

PubMed: MeSH publication types

  • Journal Article
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.


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