大肠杆菌正常细胞和诱导细胞中单链断裂的修复速率及辐照后DNA降解速率
Relative rates of repair of single-strand breaks and postirradiation DNA degradation in normal and induced cells of Escherichia coli.
作者信息
Pollard E C, Fugate J K
出版信息
Biophys J. 1978 Nov;24(2):429-37. doi: 10.1016/S0006-3495(78)85393-4.
Labeled DNA from irradiated Excherichia coli cells has been studied on an alkaline sucrose gradient without acid precipitation of the DNA. This enables the observation of both DNA repair and DNA degradation. The use of a predose of ultraviolet light (UV) causes induction of an inhibitor of postirradiation DNA degradation in lex+ strains. The effect of this induction on both the repair of single-strand breaks and DNA degradation has been followed in strains WU3610 (uvr+) and WU3610-89 (uvr-). The repair process is more rapid than the degradation, and when degradation is inhibited more repair is apparent. Cells that are lex- (Bs-1 and AB2474) cannot be induced for inhibition of degradation. Nevertheless, by observation at short times repair can be seen clearly. This repaired DNA is degraded, suggesting that the signal for DNA degradation is not a single-strand break.
对来自经辐照的大肠杆菌细胞的标记DNA在碱性蔗糖梯度上进行了研究，而无需对DNA进行酸沉淀。这使得能够观察到DNA修复和DNA降解。使用预剂量的紫外线（UV）可在lex +菌株中诱导辐照后DNA降解抑制剂。在菌株WU3610（uvr +）和WU3610 - 89（uvr-）中，已追踪到这种诱导对单链断裂修复和DNA降解的影响。修复过程比降解过程更快，并且当降解受到抑制时，更明显地观察到修复。lex-（Bs-1和AB2474）细胞不能被诱导抑制降解。然而，通过在短时间内观察，可以清楚地看到修复。这种修复的DNA会被降解，这表明DNA降解的信号不是单链断裂。
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