This gene encodes the major 3' to 5' DNA exonuclease in human cells. The protein is a non-processive exonuclease that appears to provide proofreading for checkpoint signaling after DNA damage in response to oxidative stress and apoptosis. It is ubiquitously expressed. Trex1 binds to single-stranded DNA coated with replication protein A found at sites of DNA damage, and recruits the ataxia telangiectasia and Rad3 related protein (ATR) checkpoint kinase.
