MRN complex

The MRN complex is heterotrimeric protein complex consisting of Mre11, Rad50 and Nbs1. It is involved in DNA repair in mammals. Nbs1 is referred to as Nibrin. This complex recognizes DNA damage and rapidly relocates to DSB sites and forms nuclear foci. Its activity includes end-processing of both physiological and mutagenic DNA double strand breaks (DSBs). . It appears that as part of its end-processing of DSBs, short single-strand oligonucleotides are produced, which induce activation of Ataxia Telangiectasia-Mutated (ATM), ultimately leading to activation of the DNA damage checkpoint.