RNF4 and USP7 cooperate in ubiquitin-regulated steps of DNA replication.
Ya-Chu ChangKevin LinRyan M BaxleyWesley DurrettLiangjun WangOlivera StojkovaMaximilian BillmannHenry WardChad L MyersAnja-Katrin BielinskyPublished in: Open biology (2023)
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.
Keyphrases
- small molecule
- dna damage response
- cell death
- crispr cas
- dna damage
- genome wide
- protein protein
- cell cycle arrest
- induced apoptosis
- dna repair
- genome editing
- gene expression
- copy number
- early onset
- signaling pathway
- dna methylation
- binding protein
- cell free
- cell proliferation
- single molecule
- newly diagnosed
- pi k akt
- circulating tumor cells