title: ATM signaling facilitates repair of DNA double-strand breaks associated with heterochromatin.
abstract: Ataxia Telangiectasia Mutated (ATM) signaling is essential for the repair of a subset of DNA double-strand breaks (DSBs); however, its precise role is unclear. Here, we show that < or =25% of DSBs require ATM signaling for repair, and this percentage correlates with increased chromatin but not damage complexity. Importantly, we demonstrate that heterochromatic DSBs are generally repaired more slowly than euchromatic DSBs, and ATM signaling is specifically required for DSB repair within heterochromatin. Significantly, knockdown of the transcriptional repressor KAP-1, an ATM substrate, or the heterochromatin-building factors HP1 or HDAC1/2 alleviates the requirement for ATM in DSB repair. We propose that ATM signaling temporarily perturbs heterochromatin via KAP-1, which is critical for DSB repair/processing within otherwise compacted/inflexible chromatin. In support of this, ATM signaling alters KAP-1 affinity for chromatin enriched for heterochromatic factors. These data suggest that the importance of ATM signaling for DSB repair increases as the heterochromatic component of a genome expands.
authors.affiliation: Genome Damage and Stability Centre, University of Sussex, East Sussex BN1 9RQ, UK.
authors.forename: Aaron A
authors.initials: AA
authors.lastname: Goodarzi
authors.forename: Angela T
authors.initials: AT
authors.lastname: Noon
authors.forename: Dorothee
authors.initials: D
authors.lastname: Deckbar
authors.forename: Yael
authors.initials: Y
authors.lastname: Ziv
authors.forename: Yosef
authors.initials: Y
authors.lastname: Shiloh
authors.forename: Markus
authors.initials: M
authors.lastname: Löbrich
authors.forename: Penny A
authors.initials: PA
authors.lastname: Jeggo
mesh_terms: D000818:Animals; D064007:Ataxia Telangiectasia Mutated Proteins; D018797:Cell Cycle Proteins / Q000378:metabolism*; D000090266:Chromobox Protein Homolog 5; D002868:Chromosomal Proteins, Non-Histone / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects; D004260:DNA Repair / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000378:metabolism; D004622:Embryo, Mammalian / Q000166:cytology; D005347:Fibroblasts / Q000201:enzymology / Q000528:radiation effects; D006570:Heterochromatin / Q000378:metabolism* / Q000528:radiation effects; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D006801:Humans; D051379:Mice; D041681:NIH 3T3 Cells; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D011839:Radiation, Ionizing; D012097:Repressor Proteins / Q000378:metabolism; D015398:Signal Transduction / Q000528:radiation effects; D000076183:Tripartite Motif-Containing Protein 28; D025521:Tumor Suppressor Proteins / Q000378:metabolism*
chemical_list: D018797:Cell Cycle Proteins; D002868:Chromosomal Proteins, Non-Histone; D004268:DNA-Binding Proteins; D006570:Heterochromatin; D006657:Histones; D012097:Repressor Proteins; D025521:Tumor Suppressor Proteins; C475961:gamma-H2AX protein, mouse; D000090266:Chromobox Protein Homolog 5; C101116:TRIM28 protein, human; D000076183:Tripartite Motif-Containing Protein 28; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases; D003851:Deoxyribonucleases; D006655:Histone Deacetylases