DOUBLE-STRAND BREAKS FROM SINGLE PHOTO-CHEMICAL EVENTS IN DNA CONTAINING 5-BROMOURACIL
DOUBLE-STRAND BREAKS FROM SINGLE PHOTO-CHEMICAL EVENTS IN DNA CONTAINING 5-BROMOURACIL
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DOI：
10.1016/s0006-3495(78)85410-1
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发表时间：
1978-01-01
影响因子：
3.4
通讯作者：
HUTCHINSON, F
中科院分区：
文献类型：
--
作者：
KRASIN, F;HUTCHINSON, F
紫外线照射含有低水平5-溴酸的大肠杆菌细胞，通过单一光化学事件产生DNA双链断裂，每100条单链断裂一次这样的断裂，后者在碱变性DNA中进行检测。每次“致命撞击”约产生2.5- 4次双链断裂，而伽马射线每次致命撞击约产生6次双链断裂。这些结果与假设一致，即未修复的DNA双链断裂是两种情况下的主要致命事件。对紫外线的敏感性的增加（通过集落形成能力来测量）似乎与溴链的结合数量呈线性关系（0- 20%的胸腺嘧啶），并且在DNA双螺旋的一条或两条链中结合的线性关系也大致相同。
Ultraviolet irradiation of Escherichia coli cells with a low level of 5-bromouracil incorporated produces DNA double-strand breaks by single photochemical events, one such break per 100 single-strand breaks, the latter assayed in alkali-denatured DNA. About 2.5--4 double-strand breaks are produced per "lethal hit," compared with about 6 double-strand breaks per lethal hit induced by gamma rays. These results are consistent with the hypothesis that an unrepaired DNA double-strand break is a major lethal event in both cases. The increase in sensitivity to ultraviolet (measured by colony-forming ability) seems linear in the number of bromouracils incorporated (0--20% of the thymines), and the linear relationship is much the same for incorporation in one or in both strands of the DNA double helix.