title: RNF8 and RNF168 but not HERC2 are required for DNA damage-induced ubiquitylation in chicken DT40 cells.
abstract: The ubiquitylation cascade plays an important role in the recruitment of repair factors at DNA double-strand breaks. The involvement of a growing number of ubiquitin E3 ligases adds to the complexity of the DNA damage-induced ubiquitin signaling. Here we use the genetically tractable avian cell line DT40 to investigate the role of HERC2, RNF8 and RNF168 in the DNA damage-induced ubiquitylation pathway. We show that formation of ubiquitin foci as well as cell survival after DNA damage depends on both RNF8 and RNF168. However, we find that RNF8 and RNF168 knockout cell lines respond differently to treatment with camptothecin indicating that they do not function in a strictly linear manner. Surprisingly, we show that HERC2 is required neither for survival nor for ubiquitin foci formation after DNA damage in DT40. Moreover, the E3 ubiquitin ligase activity of HERC2 is not redundant to that of RNF8 or RNF168.
authors.affiliation: Department of Biology, University of Copenhagen, DK-2200, Copenhagen N, Denmark.
authors.forename: Vibe H
authors.initials: VH
authors.lastname: Oestergaard
authors.forename: Constanze
authors.initials: C
authors.lastname: Pentzold
authors.forename: Rune Troelsgaard
authors.initials: RT
authors.lastname: Pedersen
authors.forename: Silviu
authors.initials: S
authors.lastname: Iosif
authors.forename: Arno
authors.initials: A
authors.lastname: Alpi
authors.forename: Simon
authors.initials: S
authors.lastname: Bekker-Jensen
authors.forename: Niels
authors.initials: N
authors.lastname: Mailand
authors.forename: Michael
authors.initials: M
authors.lastname: Lisby
mesh_terms: D000818:Animals; D002166:Camptothecin / Q000633:toxicity; D002460:Cell Line; D002470:Cell Survival; D002645:Chickens; D004249:DNA Damage; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D020662:Guanine Nucleotide Exchange Factors / Q000235:genetics / Q000378:metabolism; D025801:Ubiquitin / Q000378:metabolism; D044767:Ubiquitin-Protein Ligases / Q000235:genetics* / Q000378:metabolism; D054875:Ubiquitination / Q000235:genetics*
chemical_list: D004268:DNA-Binding Proteins; D020662:Guanine Nucleotide Exchange Factors; D025801:Ubiquitin; D044767:Ubiquitin-Protein Ligases; D002166:Camptothecin