title: Endogenously induced DNA double strand breaks arise in heterochromatic DNA regions and require ataxia telangiectasia mutated and Artemis for their repair.
abstract: Ataxia telangiectasia (ATM) mutated and Artemis, the proteins defective in ataxia telangiectasia and a class of Radiosensitive-Severe Combined Immunodeficiency (RS-SCID), respectively, function in the repair of DNA double strand breaks (DSBs), which arise in heterochromatic DNA (HC-DSBs) following exposure to ionizing radiation (IR). Here, we examine whether they have protective roles against oxidative damage induced and/or endogenously induced DSBs. We show that DSBs generated following acute exposure of G0/G1 cells to the oxidative damaging agent, tert-butyl hydroperoxide (TBH), are repaired with fast and slow components of similar magnitude to IR-induced DSBs and have a similar requirement for ATM and Artemis. Strikingly, DSBs accumulate in ATM(-/-) mouse embryo fibroblasts (MEFs) and in ATM or Artemis-defective human primary fibroblasts maintained for prolonged periods under confluence arrest. The accumulated DSBs localize to HC-DNA regions. Collectively, the results provide strong evidence that oxidatively induced DSBs arise in HC as well as euchromatic DNA and that Artemis and ATM function in their repair. Additionally, we show that Artemis functions downstream of ATM and is dispensable for HC-relaxation and for pKAP-1 foci formation. These findings are important for evaluating the impact of endogenously arising DNA DSBs in ATM and Artemis-deficient patients.
authors: Genome Damage and Stability Centre, University of Sussex, Brighton, BN1 9RQ, UK.
authors: Lisa
authors: L
authors: Woodbine
authors: H
authors: H
authors: Brunton
authors: A A
authors: AA
authors: Goodarzi
authors: A
authors: A
authors: Shibata
authors: P A
authors: PA
authors: Jeggo
references: J Biol Chem. 2007 Dec 14;282(50):36177-89
references: 17942393
references: Hum Mol Genet. 2003 Feb 1;12(3):227-32
references: 12554677
references: Cell Cycle. 2010 Feb 15;9(4):662-9
references: 20139725
references: Chem Biol Interact. 1998 Apr 24;111-112:113-21
references: 9679548
references: Annu Rev Genet. 2006;40:363-83
references: 16895466
references: Nature. 1996 Mar 21;380(6571):221-6
references: 8637569
references: J Biol Chem. 2008 May 23;283(21):14391-401
references: 18375387
references: J Biol Chem. 2001 Jun 15;276(24):21951-9
references: 11290740
references: Cancer Res. 1987 Sep 1;47(17):4576-81
references: 3621155
references: Mol Cell. 2004 Dec 3;16(5):715-24
references: 15574327
references: FEBS Lett. 2000 Apr 21;472(1):133-6
references: 10781820
references: J Biol Chem. 1998 Mar 6;273(10):5858-68
references: 9488723
references: Nature. 1993 Apr 22;362(6422):709-15
references: 8469282
references: Mol Cell Biol. 2003 Aug;23(16):5706-15
references: 12897142
references: Nat Cell Biol. 2003 Aug;5(8):741-7
references: 12855956
references: Cell Mol Life Sci. 2005 Sep;62(17):1938-45
references: 15990954
references: Blood. 2009 Apr 23;113(17):4114-24
references: 19168787
references: Mol Cell. 2008 Jul 25;31(2):167-77
references: 18657500
references: Cell. 2001 Apr 20;105(2):177-86
references: 11336668
references: DNA Repair (Amst). 2008 Jul 1;7(7):1028-38
references: 18456574
references: Curr Biol. 2002 Mar 5;12(5):397-402
references: 11882291
references: Radiat Res. 2001 Nov;156(5 Pt 2):577-83
references: 11604075
references: Nat Cell Biol. 2010 Feb;12(2):177-84
references: 20081839
references: Nat Cell Biol. 2006 Aug;8(8):870-6
references: 16862143
references: Nature. 2004 Oct 21;431(7011):997-1002
references: 15496926
references: Hum Mol Genet. 2007 Sep 15;16(18):2154-64
references: 17606465
references: Cancer Res. 2004 Apr 1;64(7):2390-6
references: 15059890
references: Bioessays. 1997 Oct;19(10):911-7
references: 9363685
references: Int J Radiat Biol. 1991 Jun;59(6):1325-39
references: 1677379
references: Nat Rev Cancer. 2003 Mar;3(3):155-68
references: 12612651
references: Curr Biol. 1999 Dec 16-30;9(24):1501-4
references: 10607596
references: DNA Repair (Amst). 2002 Jan 22;1(1):3-25
references: 12509294
references: Nature. 2007 Jun 7;447(7145):686-90
references: 17554302
references: Int J Radiat Biol. 2010 Aug;86(8):682-91
references: 20569192
references: Nat Rev Mol Cell Biol. 2008 Oct;9(10):759-69
references: 18813293
references: J Exp Med. 2003 Mar 3;197(5):553-65
references: 12615897