Mre11 is a component of the MRN complex, which plays a critical role in double-strand break repair (DSB), DNA recombination, maintenance of telomere integrity, and meiosis. Mre11 has both single-strand endonuclease and double strand-specific 3'-5' exonuclease activities. Rad50, another component of the MRN complex, is postulated to bind to DNA ends and hold them in close proximity, thus facilitating searches for regions of sequence homology, and also possibly stimulating the activity of DNA ligases and or restricting Mre11 activity. Mutations in Mre11 may cause breast cancer.