Involved in DNA double-strand break repair (DSBR) (PubMed:11238374). Possesses single-strand endonuclease activity and double-strand-specific 3'-5' exonuclease activity (PubMed:11238374). Also involved in meiotic DSB processing (PubMed:11238374). In response to ionizing radiation, probably required for the association between the brc-1-brd-1 heterodimer and rad-51 and let-70 in order to activate E3-ubiquitin ligase activity of the heterodimer and induce ubiquitination at DNA damage sites (PubMed:16628214). Required for meiotic crossing over and chiasma formation. Pachytene morphology and homolog pairing are normal. Vital in long term for maintenance of reproductive capacity of subsequent generations. Forms a complex with rad-50. RNAi-mediated knockdown results in DNA damage repair defects following ionizing radiation with reduced ubiquitination at DNA damage sites. Belongs to the MRE11/RAD32 family.