Repair of abasic sites in DNA.
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.
Dianov
Grigory L
GL
Radiation & Genome Stability Unit, Medical Research Council, Harwell, Oxfordshire OX11 0RD, UK. g.dianov@har.mrc.ac.uk
Sleeth
Kate M
KM
Dianova
Irina I
II
Allinson
Sarah L
SL
D001483:Base Sequence; D004260:DNA Repair; D008969:Molecular Sequence Data