Enables damaged DNA binding activity. Involved in blastocyst growth and isotype switching. Acts upstream of or within cell population proliferation; intracellular signal transduction; and neuromuscular process controlling balance. Located in PML body and replication fork. Colocalizes with chromosome, telomeric region. Is expressed in several structures, including alimentary system; brain; genitourinary system; heart; and respiratory system. Used to study Nijmegen breakage syndrome and T-cell acute lymphoblastic leukemia. Human ortholog(s) of this gene implicated in several diseases, including Nijmegen breakage syndrome; acute lymphoblastic leukemia; aplastic anemia; breast cancer; and reproductive organ cancer (multiple). Orthologous to human NBN (nibrin). [provided by Alliance of Genome Resources, Apr 2022]