A murine model of Nijmegen breakage syndrome

Curr Biol. 2002 Apr 16;12(8):648-53. doi: 10.1016/s0960-9822(02)00763-7.


Nijmegen breakage syndrome (NBS) is a rare autosomal recessive disorder characterized by microcephaly, immunodeficiency, and predisposition to hematopoietic malignancy. The clinical and cellular phenotypes of NBS substantially overlap those of ataxia-telangiectasia (A-T). NBS is caused by mutation of the NBS1 gene, which encodes a member of the Mre11 complex, a trimeric protein complex also containing Mre11 and Rad50. Several lines of evidence indicate that the ataxia-telangiectasia mutated (ATM) kinase and the Mre11 complex functionally interact. Both NBS and A-T cells exhibit ionizing radiation (IR) sensitivity and defects in the intra S phase checkpoint, resulting in radioresistant DNA synthesis (RDS)-the failure to suppress DNA replication origin firing after IR exposure. NBS1 is phosphorylated by ATM in response to IR, and this event is required for activation of the intra S phase checkpoint (the RDS checkpoint). We derived a murine model of NBS, the Nbs1(DeltaB/DeltaB) mouse. Nbs1(DeltaB/DeltaB) cells are phenotypically identical to those established from NBS patients. The Nbs1(DeltaB) allele was synthetically lethal with ATM deficiency. We propose that the ATM-Mre11 complex DNA damage response pathway is essential and that ATM or the Mre11 complex serves as a nexus to additional components of the pathway.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Ataxia Telangiectasia Mutated Proteins
  • Blotting, Southern
  • Cell Cycle
  • Cell Cycle Proteins / chemistry
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism*
  • Chromosome Breakage*
  • DNA Damage
  • DNA Repair Enzymes
  • DNA-Binding Proteins / chemistry
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Disease Models, Animal*
  • Epistasis, Genetic
  • Fibroblasts
  • Gene Deletion*
  • Genes, Lethal / genetics
  • Humans
  • MRE11 Homologue Protein
  • Mice
  • Mice, Knockout
  • Molecular Sequence Data
  • Mutation / genetics
  • Nuclear Proteins / chemistry
  • Nuclear Proteins / genetics*
  • Nuclear Proteins / metabolism*
  • Phenotype
  • Protein-Serine-Threonine Kinases / deficiency
  • Protein-Serine-Threonine Kinases / genetics
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Syndrome
  • Tumor Suppressor Proteins


  • Cell Cycle Proteins
  • DNA-Binding Proteins
  • MRE11 protein, human
  • Mre11a protein, mouse
  • Nijmegen breakage syndrome 1 protein, mouse
  • Nuclear Proteins
  • RNA, Messenger
  • Tumor Suppressor Proteins
  • ATM protein, human
  • Ataxia Telangiectasia Mutated Proteins
  • Atm protein, mouse
  • Protein-Serine-Threonine Kinases
  • MRE11 Homologue Protein
  • DNA Repair Enzymes