NCIt 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.;