title: Base excision repair of DNA in gamma-irradiated human cells.
abstract: Escherichia coli endonuclease IV was used to incise cellular DNA specifically at apurinic/apyrimidinic (AP) sites prior to alkaline elution to measure the resulting DNA strand breaks. gamma-Irradiated HeLa cells initially contained DNA strand breaks and no AP sites. Upon incubation at 37 degrees C the strand breaks were rapidly repaired and AP sites were generated and subsequently repaired. The transient nature of the AP sites indicates the in vivo operation of a base excision repair pathway whereby damaged bases are removed from DNA by DNA glycosylases to produce AP intermediates that are then substrates for AP endonucleases.
mesh_terms: D004247:DNA / Q000528:radiation effects*; D004260:DNA Repair; D005720:Gamma Rays; D006367:HeLa Cells / Q000528:radiation effects; D006801:Humans; D006863:Hydrogen-Ion Concentration
chemical_list: D004247:DNA