title: Ataxia telangiectasia mutated activation by transcription- and topoisomerase I-induced DNA double-strand breaks.
abstract: Ataxia telangiectasia mutated (ATM), the deficiency of which causes a severe neurodegenerative disease, is a crucial mediator for the DNA damage response (DDR). As neurons have high rates of transcription that require topoisomerase I (TOP1), we investigated whether TOP1 cleavage complexes (TOP1cc)-which are potent transcription-blocking lesions-also produce transcription-dependent DNA double-strand breaks (DSBs) with ATM activation. We show the induction of DSBs and DDR activation in post-mitotic primary neurons and lymphocytes treated with camptothecin, with the induction of nuclear DDR foci containing activated ATM, gamma-H2AX (phosphorylated histone H2AX), activated CHK2 (checkpoint kinase 2), MDC1 (mediator of DNA damage checkpoint 1) and 53BP1 (p53 binding protein 1). The DSB-ATM-DDR pathway was suppressed by inhibiting transcription and gamma-H2AX signals were reduced by RNase H1 transfection, which removes transcription-mediated R-loops. Thus, we propose that Top1cc produce transcription arrests with R-loop formation and generate DSBs that activate ATM in post-mitotic cells.
authors: Laboratory of Molecular Pharmacology, National Cancer Institute, NIH, Bethesda, MD 20892-4255, USA.
authors: Olivier
authors: O
authors: Sordet
authors: Christophe E
authors: CE
authors: Redon
authors: Josée
authors: J
authors: Guirouilh-Barbat
authors: Susan
authors: S
authors: Smith
authors: Stéphanie
authors: S
authors: Solier
authors: Céline
authors: C
authors: Douarre
authors: Chiara
authors: C
authors: Conti
authors: Asako J
authors: AJ
authors: Nakamura
authors: Benu B
authors: BB
authors: Das
authors: Estelle
authors: E
authors: Nicolas
authors: Kurt W
authors: KW
authors: Kohn
authors: William M
authors: WM
authors: Bonner
authors: Yves
authors: Y
authors: Pommier
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D053959:Alpha-Amanitin / Q000494:pharmacology; D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D002166:Camptothecin / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000378:metabolism*; D002478:Cells, Cultured; D053903:DNA Breaks, Double-Stranded; D004264:DNA Topoisomerases, Type I / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005434:Flow Cytometry; D006657:Histones / Q000378:metabolism; D006801:Humans; D047908:Intracellular Signaling Peptides and Proteins / Q000378:metabolism; D008214:Lymphocytes / Q000187:drug effects / Q000378:metabolism; D018613:Microscopy, Confocal; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D009687:Nuclear Proteins / Q000378:metabolism; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D051381:Rats; D016914:Ribonuclease H / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D015534:Trans-Activators / Q000378:metabolism; D014158:Transcription, Genetic / Q000235:genetics / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D000071857:Tumor Suppressor p53-Binding Protein 1
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D053959:Alpha-Amanitin; D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; C468783:H2AX protein, human; D006657:Histones; D047908:Intracellular Signaling Peptides and Proteins; C413163:MDC1 protein, human; D009687:Nuclear Proteins; D019384:Nucleic Acid Synthesis Inhibitors; C498301:TP53BP1 protein, human; D015534:Trans-Activators; D025521:Tumor Suppressor Proteins; D000071857:Tumor Suppressor p53-Binding Protein 1; D004004:Dichlororibofuranosylbenzimidazole; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; D017346:Protein Serine-Threonine Kinases; D016914:Ribonuclease H; C078856:ribonuclease HI; D004264:DNA Topoisomerases, Type I; D002166:Camptothecin