Drpase, A New Activity in the DNA Base Excision Repair Pathway

Agents that damage DNA are known to cause both mutagenesis and carcinogenic effects to cells. One specific type of DNA damage results in the loss of a purine or pyrimidine base, resulting in the formation of a base-free sugar or so-called apurinic/apyrimidinic (AP) site. Agents responsible for the induction of AP sites include gamma radiation (1), alkylating agents (2), and several other environmental and chemical carcinogens (3). AP sites can also form spontaneously in DNA (4), and they often result from the action of specific DNA glycosylases, such as uracil-DNA-glycosylase, which act to remove unusual or damaged DNA bases from DNA (5). The repair of AP sites can result in the formation of a mutation at the AP site, and such mutations may ultimately be responsible for the induction of the carcinogenic process.