Wood R D, Robins P
Imperial Cancer Research Fund, Clare Hall Laboratories, South Mimms, Herts, U.K.
Genome. 1989;31(2):601-4. doi: 10.1139/g89-112.
A system is described in which extracts from human cells can perform repair replication on DNA damaged by ultraviolet light or chemical carcinogens. Whole cell extracts from lymphoid cell lines are incubated with damaged plasmid DNA circles at 30 degrees C in the presence of ATP and the four deoxynucleoside triphosphates. Repair synthesis is monitored by the incorporation of alpha-32P-dATP into closed circular plasmid molecules. Analysis of the time course of the reaction suggests that the slowest step in repair is incision, rather than polymerization or ligation. The size of repair patches inserted into ultraviolet-irradiated DNA during a reaction was estimated by substitution of thymidine triphosphate with 5-bromodeoxyuridine triphosphate and sedimentation in alkaline cesium chloride gradients. Patches with heterogeneous sizes of less than 120 bases were observed.
本文描述了一种系统，其中来自人类细胞的提取物能够对受紫外线或化学致癌物损伤的DNA进行修复复制。将淋巴样细胞系的全细胞提取物与受损的质粒DNA环在30℃下于ATP和四种脱氧核苷三磷酸存在的条件下孵育。通过将α-32P-dATP掺入闭环质粒分子中来监测修复合成。对反应时间进程的分析表明，修复过程中最慢的步骤是切口，而不是聚合或连接。通过用5-溴脱氧尿苷三磷酸替代胸苷三磷酸并在碱性氯化铯梯度中沉降，估计了反应过程中插入紫外线照射的DNA中的修复片段的大小。观察到大小小于120个碱基的异质片段。
