Strike P
Mol Gen Genet. 1977 Nov 29;157(1):99-107. doi: 10.1007/BF00268692.
Toluene treated cells have been used to study the processes of DNA synthesis and DNA degradation in ultra-violet irradiated Escherichia coli K12. Synthesis and degradation are both shown to occur extensively if polynucleotide ligase is inhibited, and to occur to a much lesser extent if ligase activity is optimal. Extensive UV-induced DNA synthesis in toluene-treated cells requires ATP for the initial incision step, and DNA polymerase I. Extensive degradation also depends on the early ATP-dependent incision step, and the subsequent degradation shows a partial requirement for ATP. Curtailment of degradation by ligase requires DNA polymerase activity, but is not dependent upon DNA polymerase I. Apparently this process can be carried out with equal facility by either DNA polymerase II or polymerase III. These observations suggest that extensive DNA polymerase I-dependent repair synthesis and extensive DNA degradation are facets of two divergent pathways of excision repair, both of which depend upon the early uvrABC determined ATP-dependent incision step.
甲苯处理过的细胞已被用于研究紫外线照射的大肠杆菌K12中DNA合成和DNA降解的过程。如果多核苷酸连接酶受到抑制，合成和降解都被证明会大量发生；而如果连接酶活性最佳，则发生的程度要小得多。甲苯处理过的细胞中广泛的紫外线诱导DNA合成在初始切口步骤需要ATP，并且需要DNA聚合酶I。广泛的降解也依赖于早期ATP依赖的切口步骤，随后的降解对ATP有部分需求。连接酶对降解的抑制需要DNA聚合酶活性，但不依赖于DNA聚合酶I。显然，这个过程可以由DNA聚合酶II或聚合酶III同样顺利地进行。这些观察结果表明，广泛的依赖DNA聚合酶I的修复合成和广泛的DNA降解是切除修复的两条不同途径的两个方面，这两条途径都依赖于早期uvrABC决定的ATP依赖的切口步骤。
