title: Repair of abasic sites in DNA.
abstract: Repair of both normal and reduced AP sites is activated by AP endonuclease, which recognizes and cleaves a phosphodiester bond 5' to the AP site. For a short period of time an incised AP site is occupied by poly(ADP-ribose) polymerase and then DNA polymerase beta adds one nucleotide into the repair gap and simultaneously removes the 5'-sugar phosphate. Finally, the DNA ligase III/XRCC1 complex accomplishes repair by sealing disrupted DNA ends. However, long-patch BER pathway, which is involved in the removal of reduced abasic sites, requires further DNA synthesis resulting in strand displacement and the generation of a damage-containing flap that is later removed by the flap endonuclease. Strand-displacement DNA synthesis is accomplished by DNA polymerase delta/epsilon and DNA ligase I restores DNA integrity. DNA synthesis by DNA polymerase delta/epsilon is dependent on proliferating cell nuclear antigen, which also stimulates the DNA ligase I and flap endonuclease. These repair events are supported by multiple protein-protein interactions.
authors.affiliation: Radiation & Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD, UK. g.dianov@har.mrc.ac.uk
authors.forename: Grigory L
authors.initials: GL
authors.lastname: Dianov
authors.forename: Kate M
authors.initials: KM
authors.lastname: Sleeth
authors.forename: Irina I
authors.initials: II
authors.lastname: Dianova
authors.forename: Sarah L
authors.initials: SL
authors.lastname: Allinson
mesh_terms: D001483:Base Sequence; D004260:DNA Repair; D008969:Molecular Sequence Data