MRE11A（MRE11 homolog A， double strand break repair nuclease），癌症关联基因，基因ID：4361，该基因编码一种参与同源重组、端粒长度维持和DNA双链断裂修复的核蛋白。该蛋白本身具有3’到5’的核酸外切酶活性和核酸内切酶活性。该蛋白与RAD50同系物形成复合物；该复合物是DNA末端非同源连接所必需的，具有增加的单链DNA内切酶和3’到5’的外切酶活性。该蛋白与DNA连接酶结合，在体外利用靠近DNA片段末端的短同源性促进非完全末端的连接。这个基因在3号染色体上有一个假基因。该基因的选择性剪接导致编码不同亚型的两个转录变体。This gene encodes a nuclear protein involved in homologous recombination， telomere length maintenance， and DNA double-strand break repair. By itself， the protein has 3' to 5' exonuclease activity and endonuclease activity. The protein forms a complex with the RAD50 homolog; this complex is required for nonhomologous joining of DNA ends and possesses increased single-stranded DNA endonuclease and 3' to 5' exonuclease activities. In conjunction with a DNA ligase， this protein promotes the joining of noncomplementary ends in vitro using short homologies near the ends of the DNA fragments. This gene has a pseudogene on chromosome 3. Alternative splicing。