PSORALEN ADDUCTS IN A SHUTTLE VECTOR PLASMID PROPAGATED IN PRIMATE CELLS - HIGH MUTAGENICITY OF DNA CROSS-LINKS
PSORALEN ADDUCTS IN A SHUTTLE VECTOR PLASMID PROPAGATED IN PRIMATE CELLS - HIGH MUTAGENICITY OF DNA CROSS-LINKS
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DOI：
10.1093/carcin/8.12.1923
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发表时间：
1987-12-01
期刊：
影响因子：
4.7
通讯作者：
NACHMANSSON, N
中科院分区：
文献类型：
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作者：
BREDBERG, A;NACHMANSSON, N
将猿病毒 40 驱动的穿梭载体质粒 (pZ189) 用 8-甲氧基补骨脂素加分次剂量的长波紫外线 (UVA) 辐射处理，以便与单加合物相比，在质粒 DNA 中形成大量补骨脂素交联。然后将穿梭载体转染至猴 Vero 或人 Raji 细胞中。 2 天后提取在灵长类宿主细胞中复制的质粒并分析载体抑制 tRNA (supF) 基因的突变。自发突变频率为0.7倍。在暴露于补骨脂素和两次 UVA 照射的载体中，10-3 升高了 15 倍。大多数这些突变被认为依赖于 DNA 交联加合物，因为补骨脂素仅加上单次 UVA 剂量（主要产生单加合物）不会明显影响突变率。 DNA序列分析揭示了AT重复的热点构成了补骨脂素交联形成的潜在位点，而所指出的第二个热点不包含任何可能发生补骨脂素加合物形成的序列。由于 AT 重复热点在之前的 pZ189 暴露于其他基因毒性剂的研究中并未得到体现，因此结果表明特定的突变模式可能是由 DNA 交联的诱导产生的。
A Simian virus 40-driven shuttle vector plasmid (pZ189) was treated with 8-methoxypsoralen plus a split dose of long-wavelength UV (UVA) radiation in order for a large number of psoralen cross-links, as compared with monoadducts, to be formed in the plasmid DNA. The shuttle vector was then transfected into monkey Vero or human Raji cells. Plasmids replicated in the primate host cell were extracted 2 days later and analysed for mutations in the vector suppressor tRNA (supF) gene. A spontaneous mutation frequency of 0.7 .times. 10-3 was 15-fold elevated in vectors exposed to psoralen plus two UVA irradiations. Most of these mutations were considered to be dependent on DNA cross-link adducts, since psoralen plus only a single UVA dose (producing mainly monoadducts) did not appreciably affect the mutation rate. DNA sequence analysis revealed a hot spot at an AT repeat constituting a potential site for psoralen cross-link formation, whereas the second hot spot noted did not contain any sequence where psoralen adduct formation is likely to occur. Since the AT repeat hot spot was not represented in previous studies with pZ189 exposed to other genotoxic agents, the results indicate that a specific mutational pattern may be resulting from induction of DNA cross-links.