Required for maintenance of chromosomal stability. Promotes accurate and efficient pairing of homologs during meiosis. Involved in the repair of DNA double-strand breaks, both by homologous recombination and single-strand annealing. May participate in S phase and G2 phase checkpoint activation upon DNA damage. Plays a role in preventing breakage and loss of missegregating chromatin at the end of cell division, particularly after replication stress. Required for the targeting, or stabilization, of BLM to non-centromeric abnormal structures induced by replicative stress. Promotes BRCA2/FANCD1 loading onto damaged chromatin. May also be involved in B-cell immunoglobulin isotype switching. Ho GP, Margossian S, Taniguchi T, D'Andrea AD (2006)Mol Cell Biol 26, 7005-15. Nakanishi K, et al. (2002)Nat Cell Biol 4, 913-20. Taniguchi T, et al. (2002) Cell 109, 459-72 .