Base Excision Repair

**Semantic type:** Genetic Function

**Definition:** Initiation of DNA base excision repair (BER) involves a DNA glycosylase that binds the altered deoxynucleoside in an extrahelical position and catalyzes cleavage of the base-sugar bond. Subsequently, an AP endonuclease or AP lyase activity incises the abasic site, followed by short-patch gap-filling, excision of the base-free sugar-phosphate residue, and ligation.

**Synonyms:** - BER - DNA Base Excision Repair