title: RNF4 is required for DNA double-strand break repair in vivo.
abstract: Unrepaired DNA double-strand breaks (DSBs) cause genetic instability that leads to malignant transformation or cell death. Cells respond to DSBs with the ordered recruitment of signaling and repair proteins to the sites of DNA lesions. Coordinated protein SUMOylation and ubiquitylation have crucial roles in regulating the dynamic assembly of protein complexes at these sites. However, how SUMOylation influences protein ubiquitylation at DSBs is poorly understood. We show herein that Rnf4, an E3 ubiquitin ligase that targets SUMO-modified proteins, accumulates in DSB repair foci and is required for both homologous recombination (HR) and non-homologous end joining repair. To establish a link between Rnf4 and the DNA damage response (DDR) in vivo, we generated an Rnf4 allelic series in mice. We show that Rnf4-deficiency causes persistent ionizing radiation-induced DNA damage and signaling, and that Rnf4-deficient cells and mice exhibit increased sensitivity to genotoxic stress. Mechanistically, we show that Rnf4 targets SUMOylated MDC1 and SUMOylated BRCA1, and is required for the loading of Rad51, an enzyme required for HR repair, onto sites of DNA damage. Similarly to inactivating mutations in other key regulators of HR repair, Rnf4 deficiency leads to age-dependent impairment in spermatogenesis. These findings identify Rnf4 as a critical component of the DDR in vivo and support the possibility that Rnf4 controls protein localization at DNA damage sites by integrating SUMOylation and ubiquitylation events.
authors.affiliation: Center for the Biology of Disease, Laboratory for Molecular Cancer Biology, VIB, Leuven, Belgium.
authors.forename: R
authors.initials: R
authors.lastname: Vyas
authors.forename: R
authors.initials: R
authors.lastname: Kumar
authors.forename: F
authors.initials: F
authors.lastname: Clermont
authors.forename: A
authors.initials: A
authors.lastname: Helfricht
authors.forename: P
authors.initials: P
authors.lastname: Kalev
authors.forename: P
authors.initials: P
authors.lastname: Sotiropoulou
authors.forename: I A
authors.initials: IA
authors.lastname: Hendriks
authors.forename: E
authors.initials: E
authors.lastname: Radaelli
authors.forename: T
authors.initials: T
authors.lastname: Hochepied
authors.forename: C
authors.initials: C
authors.lastname: Blanpain
authors.forename: A
authors.initials: A
authors.lastname: Sablina
authors.forename: H
authors.initials: H
authors.lastname: van Attikum
authors.forename: J V
authors.initials: JV
authors.lastname: Olsen
authors.forename: A G
authors.initials: AG
authors.lastname: Jochemsen
authors.forename: A C O
authors.initials: AC
authors.lastname: Vertegaal
authors.forename: J-C
authors.initials: JC
authors.lastname: Marine
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000483:Alleles; D000818:Animals; D019313:BRCA1 Protein / Q000378:metabolism; D018797:Cell Cycle Proteins; D002460:Cell Line; D053903:DNA Breaks, Double-Stranded; D004260:DNA Repair; D005838:Genotype; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D051379:Mice; D008822:Mice, Transgenic; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D051135:Rad51 Recombinase / Q000378:metabolism; D011839:Radiation, Ionizing; D058207:Sumoylation; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D044767:Ubiquitin-Protein Ligases; D054875:Ubiquitination
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D019313:BRCA1 Protein; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; C508937:MDC1 protein, mouse; D009687:Nuclear Proteins; D014157:Transcription Factors; C486410:Rnf4 protein, mouse; D044767:Ubiquitin-Protein Ligases; D051135:Rad51 Recombinase