Repair of quercetin-induced single-strand breaks by a cell free system.
Repair of quercetin-induced single-strand breaks of DNA was studied in vitro using cell free extract from GM 00637D cells, a human cell line. Single-strand breaks were introduced into DNA by the treatment of closed circular, superhelical form of pBR322 plasmid DNA with quercetin and Cu(II). Repair of these breaks was demonstrated by agarose gel electrophoresis after incubating damaged DNA with cell extract, DNA polymerase I (klenow fragment of DNA polymerase), four deoxynucleotide triphosphates, ATP and T4 DNA ligase. The present results suggested that 1) the exonuclease is involved in the initiation of repair of quercetin-induced single-strand breaks by removing the 3' ends of quercetin damaged DNA and 2) oxygen free radicals are involved in quercetin-induced DNA strand scission.
Department of Radiology, Ohio State University, Columbus 43210.
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D002460:Cell Line; D002474:Cell-Free System; D004249:DNA Damage; D011088:DNA Ligases / Q000378:metabolism; D004260:DNA Repair; D004270:DNA, Circular / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D004278:DNA, Superhelical / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D010957:Plasmids; D011794:Quercetin / Q000633:toxicity*
D004270:DNA, Circular; D004278:DNA, Superhelical; D011794:Quercetin; D011088:DNA Ligases