Nonenzymatic release of N7-methylguanine channels repair of abasic sites into an AP endonuclease-independent pathway in Arabidopsis.

ABSTRACT: Abasic (apurinic/apyrimidinic, AP) sites in DNA arise from spontaneous base loss or by enzymatic removal during base excision repair. It is commonly accepted that both classes of AP site have analogous biochemical properties and are equivalent substrates for AP endonucleases and AP lyases, although the relative roles of these two types of enzymes are not well understood. We provide here genetic and biochemical evidence that, in Arabidopsis, AP sites generated by spontaneous loss of N7-methylguanine (N7-meG) are exclusively repaired through an AP endonuclease-independent pathway initiated by FPG, a bifunctional DNA glycosylase with AP lyase activity. Abasic site incision catalyzed by FPG generates a single-nucleotide gap with a 3'-phosphate terminus that is processed by the DNA 3'-ph

SUBMITTER: Barbado C 

PROVIDER: S-EPMC5798382 | biostudies-literature | 2018 Jan

REPOSITORIES: biostudies-literature