Repair of X-ray-induced single-strand breaks by a cell-free system.
Repair of X-ray-induced single-strand breaks of DNA was studied in vitro using an exonuclease purified from mouse ascites sarcoma (SR-C3H/He) cells. X-ray-dose-dependent unscheduled DNA synthesis was primed by the exonuclease. Repair of X-ray-induced single-strand breaks in pUC19 plasmid DNA was demonstrated by agarose gel electrophoresis after incubating the damaged DNA with the exonuclease, DNA polymerase (Klenow fragment of DNA polymerase I or DNA polymerase beta purified from SR-C3H/He cells), four deoxynucleoside triphosphates, ATP and DNA ligase (T4 DNA ligase or DNA ligase I purified from calf thymus). The present results suggested that the exonuclease is involved in the initiation of repair of X-ray-induced single-strand breaks in removing 3' ends of X-ray-damaged DNA.
Seki
S
S
Department of Biochemistry, Okayama University Medical School, Japan.
Ikeda
S
S
Tsutui
K
K
Teraoka
H
H
D000818:Animals; D002474:Cell-Free System; D004249:DNA Damage; D004260:DNA Repair / Q000502:physiology* / Q000528:radiation effects; D004273:DNA, Neoplasm / Q000528:radiation effects; D004277:DNA, Single-Stranded; D051379:Mice; D009690:Nucleic Acid Conformation; D011829:Radiation Dosage; D012513:Sarcoma, Experimental / Q000235:genetics; D013698:Templates, Genetic
D004273:DNA, Neoplasm; D004277:DNA, Single-Stranded