title: Distinct domains in Nbs1 regulate irradiation-induced checkpoints and apoptosis.
abstract: The chromosomal instability syndromes Nijmegen breakage syndrome (NBS) and ataxia telangiectasia (AT) share many overlapping phenotypes, including cancer predisposition, radiation sensitivity, cell-cycle checkpoint defects, immunodeficiency, and gonadal dysfunction. The NBS protein Nbs1 is not only a downstream target of AT mutated (ATM) kinase but also acts upstream, promoting optimal ATM activation, ATM recruitment to breaks, and ATM accessibility to substrates. By reconstituting Nbs1 knockout mice with bacterial artificial chromosomes, we have assessed the contribution of distinct regions of Nbs1 to the ATM-dependent DNA damage response. We find that T cell and oocyte development, as well as DNA damage-induced G2/M and S phase checkpoint arrest and radiation survival are dependent on the N-terminal forkhead-associated domain, but not on the principal residues phosphorylated by ATM (S278 and S343) or on the evolutionarily conserved C-terminal region of Nbs1. However, the C-terminal region regulates irradiation-induced apoptosis. These studies provide insight into the complex interplay between Nbs1 and ATM in the DNA damage response.
authors.affiliation: Experimental Immunology Branch and 3Genetics Branch, National Cancer Institute, National Institutes of Health, Bethesda, MD 20892, USA.
authors.forename: Simone
authors.initials: S
authors.lastname: Difilippantonio
authors.forename: Arkady
authors.initials: A
authors.lastname: Celeste
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Kruhlak
authors.forename: Youngsoo
authors.initials: Y
authors.lastname: Lee
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Difilippantonio
authors.forename: Lionel
authors.initials: L
authors.lastname: Feigenbaum
authors.forename: Stephen P
authors.initials: SP
authors.lastname: Jackson
authors.forename: Peter J
authors.initials: PJ
authors.lastname: McKinnon
authors.forename: André
authors.initials: A
authors.lastname: Nussenzweig
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000502:physiology*; D064007:Ataxia Telangiectasia Mutated Proteins; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D043171:Chromosomal Instability / Q000502:physiology*; D022202:Chromosomes, Artificial, Bacterial; D004249:DNA Damage / Q000502:physiology*; D017931:DNA Primers; D004268:DNA-Binding Proteins / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D047468:Immunoprecipitation; D020287:In Situ Nick-End Labeling; D051379:Mice; D018345:Mice, Knockout; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism*; D009865:Oocytes / Q000254:growth & development; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism; D017434:Protein Structure, Tertiary; D013601:T-Lymphocytes / Q000502:physiology; D025521:Tumor Suppressor Proteins / Q000378:metabolism
chemical_list: D018797:Cell Cycle Proteins; D017931:DNA Primers; D004268:DNA-Binding Proteins; C112156:NBN protein, human; D009687:Nuclear Proteins; D025521:Tumor Suppressor Proteins; C576324:ATM protein, human; D064007:Ataxia Telangiectasia Mutated Proteins; C576325:Atm protein, mouse; D017346:Protein Serine-Threonine Kinases