APE1 is the major 3'-phosphoglycolate activity in human cell extracts.
DNA strand breaks containing 3'-phosphoglycolate (3'-PG) ends are the major lesions induced by ionizing radiation. The repair of this lesion is not completely understood and several activities are thought to be involved in processing of 3'-PG ends. In this study we examined activities in human whole cell extracts (WCE) responsible for removal of 3'-PG. Using a radiolabelled oligonucleotide containing a single nucleotide gap with internal 5'-phosphate and 3'-PG ends, we demonstrate that the major 3'-PG activity in human WCE is Mg2+ dependent and that this activity co-purifies with AP endonuclease 1 (APE1) over phosphocellulose and gel filtration chromatography. Furthermore, immunodepletion of APE1 from active gel filtration fractions using APE1 specific antibodies reveals that the major activity against 3'-PG in human WCE is APE1.
Parsons
Jason L
JL
MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD, UK.
Dianova
Irina I
II
Dianov
Grigory L
GL
D002457:Cell Extracts / Q000737:chemistry; D004260:DNA Repair; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000302:isolation & purification / Q000378:metabolism*; D006016:Glycolates / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D009841:Oligonucleotides / Q000378:metabolism; D011233:Precipitin Tests
D002457:Cell Extracts; D006016:Glycolates; D009841:Oligonucleotides; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; C013193:phosphoglycolate