title: Role for Artemis nuclease in the repair of radiation-induced DNA double strand breaks by alternative end joining.
abstract: Exposure of cells to ionizing radiation or radiomimetic drugs generates DNA double-strand breaks that are processed either by homologous recombination repair (HRR), or by canonical, DNA-PKcs-dependent non-homologous end-joining (C-NHEJ). Chemical or genetic inactivation of factors involved in C-NHEJ or HRR, but also their local failure in repair proficient cells, promotes an alternative, error-prone end-joining pathway that serves as backup (A-EJ). There is evidence for the involvement of Artemis endonuclease, a protein deficient in a human radiosensitivity syndrome associated with severe immunodeficiency (RS-SCID), in the processing of subsets of DSBs by HRR or C-NHEJ. It is thought that within HRR or C-NHEJ Artemis processes DNA termini at complex DSBs. Whether Artemis has a role in A-EJ remains unknown. Here, we analyze using pulsed-field gel electrophoresis (PFGE) and specialized reporter assays, DSB repair in wild-type pre-B NALM-6 lymphocytes, as well as in their Artemis(-/-), DNA ligase 4(-/-) (LIG4(-/-)), and LIG4(-/-)/Artemis(-/-) double mutant counterparts, under conditions allowing evaluation of A-EJ. Our results substantiate the suggested roles of Artemis in C-NHEJ and HRR, but also demonstrate a role for the protein in A-EJ that is confirmed in Artemis deficient normal human fibroblasts. We conclude that Artemis is a nuclease participating in DSB repair by all major repair pathways.
authors.affiliation: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany.
authors.forename: Mario
authors.initials: M
authors.lastname: Moscariello
authors.affiliation: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany.
authors.forename: Radi
authors.initials: R
authors.lastname: Wieloch
authors.affiliation: Graduate School of Nanobioscience and Advanced Medical Research Center, Yokohama City University, Yokohama, Japan.
authors.forename: Aya
authors.initials: A
authors.lastname: Kurosawa
authors.affiliation: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany.
authors.forename: Fanghua
authors.initials: F
authors.lastname: Li
authors.affiliation: Graduate School of Nanobioscience and Advanced Medical Research Center, Yokohama City University, Yokohama, Japan.
authors.forename: Noritaka
authors.initials: N
authors.lastname: Adachi
authors.affiliation: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany. Electronic address: Emil.Mladenov@uk-essen.de.
authors.forename: Emil
authors.initials: E
authors.lastname: Mladenov
authors.affiliation: Institute of Medical Radiation Biology, University of Duisburg-Essen Medical School, Essen, Germany. Electronic address: Georg.Iliakis@uk-essen.de.
authors.forename: George
authors.initials: G
authors.lastname: Iliakis
mesh_terms: D002453:Cell Cycle; D045744:Cell Line, Tumor; D002843:Chromatin / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded; D059766:DNA End-Joining Repair; D000072481:DNA Ligase ATP; D011088:DNA Ligases / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D004268:DNA-Binding Proteins; D016521:Electrophoresis, Gel, Pulsed-Field; D004720:Endonucleases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D016195:G2 Phase; D006801:Humans; D011995:Recombination, Genetic; D016511:Severe Combined Immunodeficiency
chemical_list: D002843:Chromatin; D004268:DNA-Binding Proteins; C000607893:LIG4 protein, human; C426344:DCLRE1C protein, human; D004720:Endonucleases; D011088:DNA Ligases; D000072481:DNA Ligase ATP
keywords: Alternative end joining (A-EJ); Artemis nuclease; DNA double-strand breaks (DSBs); Ionizing radiation (IR); Non-homologous end-joining (NHEJ)