Bil'din V N, Seregina T B, Zhestianikov B D
Tsitologiia. 1992;34(9):32-42.
A study was made of the repair of ionizing radiation-induced DNA single-strand breaks (SSB) in proliferating and quiescent mouse Swiss 3T6 cells and in those stimulated from the quiet status by epidermal growth factor in combination with insulin, in the presence of specific inhibitors of DNA polymerase alpha and delta (aphidicolin) and DNA polymerase beta (2', 3'-dideoxythymidine-5'-triphosphate). The repair of DNA SSB induced by X-ray-irradiation (10 Gr) or by gamma-ray irradiation (150 Gr) is more sensitive to aphidicolin independently of cell proliferating status. Aphidicolin inhibits the recovery of single-strand DNA in quiescent and mitogen-stimulated cells three times stronger than in proliferating cells. The influence of 2', 3'-dideoxythymidine-5'-triphosphate on the rate of DNA SSB repair in cells of all the three types does not differ. Thus, the decrease in DNA repair efficiency in quiescent cells is connected with a decrease in the activity of aphidicolin-sensitive DNA polymerase, apparently DNA polymerase alpha. It is suggested that the regulation action of mitogens on the DNA SSB repair may be determined by qualitative changes of this enzyme or of some conditions in which it functions. The involvement of DNA polymerase delta in this process is not excluded.
对增殖和静止的小鼠瑞士3T6细胞以及那些通过表皮生长因子联合胰岛素从静止状态刺激而来的细胞，在存在DNA聚合酶α和δ的特异性抑制剂（阿非迪霉素）以及DNA聚合酶β（2', 3'-二脱氧胸苷-5'-三磷酸）的情况下，研究了电离辐射诱导的DNA单链断裂（SSB）的修复情况。X射线照射（10戈瑞）或γ射线照射（150戈瑞）诱导的DNA SSB修复对阿非迪霉素更敏感，与细胞增殖状态无关。阿非迪霉素抑制静止和有丝分裂原刺激细胞中单链DNA的恢复，其抑制作用比增殖细胞强三倍。2', 3'-二脱氧胸苷-5'-三磷酸对所有三种类型细胞中DNA SSB修复速率的影响没有差异。因此，静止细胞中DNA修复效率的降低与阿非迪霉素敏感的DNA聚合酶（显然是DNA聚合酶α）活性的降低有关。有人提出，有丝分裂原对DNA SSB修复的调节作用可能由该酶的定性变化或其发挥作用的某些条件决定。不排除DNA聚合酶δ参与这一过程。
