NBS1 (Nijmegen breakage syndrome protein 1) is a component of the MRN complex (Mre11-Rad50-Nbs1) that plays important role in detecting DNA double strand breaks (DSBs) and triggering the downstream cascade. DSBs can be caused by ionizing radiation, chemotherapy drugs, metabolic ROS, replication errors, programmed enzymatic activities during meiosis/V(D)J recombination, etc.
