摘要
The roles of DNA polymerase β in the repair synthesis of γ-rays irradiated DNA from calf thymus .SMMC-LTNM hepatoma and nude mouse hepatocytes were evaluated, using NEM or d2TTP as selective inhibitors to DNA polymerase a or β . It was observed that the rate of [3H]-TTP incorporating into calf thymus DNA damaged by 10 Gy γ-ray was much higher( P<0.01 ) than that of the non-irradiated one. when there was some amount of recombinant rat DNA polymerase β in the reaction mixture. We also found that the [3H]-TTP incorporation rate reflecting the DNA repair synthesis increased gradually as γ-rays absorbed doserose to 20 Gy for hepatocyte nuclei or to 5 Gy for hepatoma nuclei. and then decreased slowly as the absorbeddose rose higher. These results suggest that DNA polyrnerase β could participate in DNA repair synthesis inboth normal and neoplastic nuclei irradiated by γ-rays and its roles in DNA repair may be related to cell typesand absorbed dose.
