InterPro domain: IPR040227

Nibrin (also known as Nbs1 or p95) plays an important role in the DNA damage response (DDR) and DNA repair. It is part of the nuclear MRN complex, which consists of Mre11, Rad50, and Nbs1, and is involved in double-strand break (DSB) repair, DNA recombination, maintenance of telomere integrity, cell cycle checkpoint control and meiosis [ 1 , 2 , 3 , 4 , 5 , 6 ]. Mutations in the NBN gene coding for nibrin cause the Nijmegen Breakage Syndrome (NBS), a rare autosomal recessive disorder characterised by genomic instability and increased risk of haematopoietic malignancies [ 7 , 8 ].

NBS1 homologues from plants are also involved in DNA repair and recombination [ 9 ]. In S. pombe, Nbs1 is required for DNA damage repair and S-phase DNA damage checkpoint [ 10 , 11 ].

1. Nuclease activities in a complex of human recombination and DNA repair factors Rad50, Mre11, and p95. J. Biol. Chem. 273, 21447-50
2. Cell-cycle-regulated association of RAD50/MRE11/NBS1 with TRF2 and human telomeres. Nat. Genet. 25, 347-52
3. N terminus of CtIP is critical for homologous recombination-mediated double-strand break repair. J. Biol. Chem. 284, 31746-52
4. Rescue of a telomere length defect of Nijmegen breakage syndrome cells requires NBS and telomerase catalytic subunit. Curr. Biol. 11, 962-6
5. Nibrin functions in Ig class-switch recombination. Proc. Natl. Acad. Sci. U.S.A. 102, 1584-9
6. Nbs1 is essential for DNA repair by homologous recombination in higher vertebrate cells. Nature 420, 93-8
7. Nijmegen breakage syndrome (NBS). Orphanet J Rare Dis 7, 13
8. The role of nibrin in doxorubicin-induced apoptosis and cell senescence in Nijmegen Breakage Syndrome patients lymphocytes. PLoS ONE 9, e104964
9. NBS1 is involved in DNA repair and plays a synergistic role with ATM in mediating meiotic homologous recombination in plants. Plant J. 52, 41-52
10. Molecular characterization of the Schizosaccharomyces pombe nbs1+ gene involved in DNA repair and telomere maintenance. Mol. Cell. Biol. 23, 6553-63
11. The fission yeast Rad32 (Mre11)-Rad50-Nbs1 complex is required for the S-phase DNA damage checkpoint. Mol. Cell. Biol. 23, 6564-73