NEIL2-initiated, APE-independent repair of oxidized bases in DNA: Evidence for a repair complex in human cells

DNA Repair (Amst). 2006 Dec 9;5(12):1439-48. doi: 10.1016/j.dnarep.2006.07.003. Epub 2006 Sep 18.


DNA glycosylases/AP lyases initiate repair of oxidized bases in the genomes of all organisms by excising these lesions and then cleaving the DNA strand at the resulting abasic (AP) sites and generate 3' phospho alpha,beta-unsaturated aldehyde (3' PUA) or 3' phosphate (3' P) terminus. In Escherichia coli, the AP-endonucleases (APEs) hydrolyze both 3' blocking groups (3' PUA and 3' P) to generate the 3'-OH termini needed for repair synthesis. In mammalian cells, the previously characterized DNA glycosylases, NTH1 and OGG1, produce 3' PUA, which is removed by the only AP-endonuclease, APE1. However, APE1 is barely active in removing 3' phosphate generated by the recently discovered mammalian DNA glycosylases NEIL1 and NEIL2. We showed earlier that the 3' phosphate generated by NEIL1 is efficiently removed by polynucleotide kinase (PNK) and not APE1. Here we show that the NEIL2-initiated repair of 5-hydroxyuracil (5-OHU) similarly requires PNK. We have also observed stable interaction between NEIL2 and other BER proteins DNA polymerase beta (Pol beta), DNA ligase IIIalpha (Lig IIIalpha) and XRCC1. In spite of their limited sequence homology, NEIL1 and NEIL2 interact with the same domains of Pol beta and Lig IIIalpha. Surprisingly, while the catalytically dispensable C-terminal region of NEIL1 is the common interacting domain, the essential N-terminal segment of NEIL2 is involved in analogous interaction. The BER proteins including NEIL2, PNK, Pol beta, Lig IIIalpha and XRCC1 (but not APE1) could be isolated as a complex from human cells, competent for repair of 5-OHU in plasmid DNA.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Cell Line
  • Cell Line, Tumor
  • DNA / metabolism*
  • DNA Glycosylases / isolation & purification
  • DNA Glycosylases / metabolism*
  • DNA Ligase ATP
  • DNA Ligases / isolation & purification
  • DNA Ligases / metabolism
  • DNA Polymerase beta / isolation & purification
  • DNA Polymerase beta / metabolism
  • DNA Repair*
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / isolation & purification
  • DNA-(Apurinic or Apyrimidinic Site) Lyase / metabolism*
  • Humans
  • Multiprotein Complexes
  • Plasmids / metabolism
  • Poly-ADP-Ribose Binding Proteins
  • Polynucleotide 5'-Hydroxyl-Kinase / isolation & purification
  • Polynucleotide 5'-Hydroxyl-Kinase / metabolism*
  • Protein Structure, Tertiary
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Transfection
  • Two-Hybrid System Techniques
  • Xenopus Proteins


  • Multiprotein Complexes
  • Poly-ADP-Ribose Binding Proteins
  • Recombinant Proteins
  • Xenopus Proteins
  • DNA
  • Polynucleotide 5'-Hydroxyl-Kinase
  • DNA Polymerase beta
  • DNA Glycosylases
  • oxoguanine glycosylase 1, human
  • APEX1 protein, human
  • DNA-(Apurinic or Apyrimidinic Site) Lyase
  • NEIL2 protein, human
  • DNA Ligases
  • DNA Ligase ATP
  • DNA ligase III alpha protein, Xenopus