大肠杆菌中经补骨脂素加近紫外辐射损伤的转化质粒DNA的修复
Repair in E. coli of transforming plasmid DNA damaged by psoralen plus near-ultraviolet irradiation.
作者信息
Roberts R J, Strike P
出版信息
Mutat Res. 1986 Mar;165(2):81-8. doi: 10.1016/0167-8817(86)90063-5.
Treatment of DNA with psoralen plus near-ultraviolet irradiation gives rise to both monoadducts and cross-links. We have examined the repair of plasmid NTP16 DNA treated in this way in vitro and then used to transform E. coli. Monoadducts are found to be potentially lethal, and can be repaired by uvr-dependent and recA-dependent pathways. The presence of a related resident plasmid in the transformed cells can enhance the survival of the incoming damaged NTP16 DNA. This effect is not recA-dependent, and a similar effect (designated "resident enhanced repair") has been observed previously with UV-irradiated plasmids of this particular incompatibility group. Removal of unbound psoralen from the plasmid DNA and exposure to further NUV is known to increase the ratio of cross-links to monoadducts, and we demonstrate that such cross-linked plasmid DNA is not readily repaired following transformation. However in the presence of homologous DNA (related resident plasmid) there is evidence for the repair, and hence uptake by the cell, of cross-linked DNA.
用补骨脂素加近紫外辐射处理DNA会产生单加成物和交联物。我们已经研究了以这种方式体外处理后用于转化大肠杆菌的质粒NTP16 DNA的修复情况。发现单加成物具有潜在致死性，可通过uvr依赖性和recA依赖性途径进行修复。转化细胞中相关常驻质粒的存在可提高导入的受损NTP16 DNA的存活率。这种效应不依赖recA，并且先前在该特定不相容组的紫外线照射质粒中也观察到了类似的效应（称为“常驻增强修复”）。从质粒DNA中去除未结合的补骨脂素并进一步暴露于近紫外线下，已知会增加交联物与单加成物的比例，并且我们证明，这种交联的质粒DNA在转化后不易修复。然而，在存在同源DNA（相关常驻质粒）的情况下，有证据表明交联DNA可被修复并因此被细胞摄取。
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