Wang T C, Smith K C
Carcinogenesis. 1986 Mar;7(3):389-92. doi: 10.1093/carcin/7.3.389.
A neutral filter elution assay was used to determine if the postreplicational formation and repair of DNA double-strand breaks (DSB) occurs in u.v.-irradiated human cells. Excision-deficient XP12 cells were pulse-labeled with [3H]thymidine after u.v. irradiation (1.5-3 J/m2), and the nascent DNA was followed during repair incubation. With increasing u.v. radiation fluences, an increasing fraction of DNA was eluted at a fast rate, indicating that DSB were produced. The maximum yield of DSB was observed after about 24 h of postirradiation incubation at 37 degrees C. Similar results were also obtained with repair-proficient VA13 cells when irradiated at much higher fluences (7.5-15 J/m2). It is concluded that, at the u.v. radiation fluences used in this work, the DSB produced in u.v.-irradiated human cells are the result of post-replication repair events, and at incubation times greater than 24 h some of these DSB are repaired.
采用中性滤膜洗脱试验来确定紫外线照射的人细胞中是否会发生DNA双链断裂（DSB）的复制后形成及修复。紫外线照射（1.5 - 3 J/m²）后，对切除缺陷型XP12细胞用[³H]胸腺嘧啶进行脉冲标记，并在修复孵育过程中追踪新生DNA。随着紫外线辐射通量增加，越来越多的DNA以快速率被洗脱，表明产生了DSB。在37℃照射后孵育约24小时后观察到DSB的最大产量。当以更高通量（7.5 - 15 J/m²）照射时，修复能力正常的VA13细胞也得到了类似结果。得出的结论是，在本研究使用的紫外线辐射通量下，紫外线照射的人细胞中产生的DSB是复制后修复事件的结果，并且在孵育时间大于24小时时，其中一些DSB会被修复。
