Piette J, Gamper H B, van de Vorst A, Hearst J E
Laboratory of Experimental Physics, University of Liège, Belgium.
Nucleic Acids Res. 1988 Nov 11;16(21):9961-77. doi: 10.1093/nar/16.21.9961.
Closed circular double stranded M13mp19 DNA containing a site-specifically placed HMT (4'-hydroxymethyl-4-5'-8-trimethylpsoralen) monoadduct or crosslink was synthesized in vitro. The damaged DNA were scored for loss of infectivity by transfection into repair proficient or deficient E. coli and into SOS induced E. coli. Mutant phages were detected by the loss of alpha-complementation between the viral and the host Lac Z genes or by the acquisition of resistance to kpn I digestion. Our results indicate that HMT mutagenesis is targeted and that deletion or transversion of the modified thymidine is the predominant sequence change elicited by a monoadduct or a crosslink. Transfection of the monoadducted DNA into a Uvr A deficient strain did not change the mutation pattern but did increase the respective mutation frequencies. Transfection of the crosslinked DNA into a SOS induced host resulted in the appearence of other types of mutations attributable to an increase in both targeted and untargeted mutations.
体外合成了含有位点特异性放置的HMT（4'-羟甲基-4,5'-8-三甲基补骨脂素）单加合物或交联的闭环双链M13mp19 DNA。通过转染到修复 proficient 或 deficient 的大肠杆菌以及 SOS 诱导的大肠杆菌中，对受损 DNA 的感染性丧失进行评分。通过病毒和宿主 Lac Z 基因之间α互补的丧失或通过获得对 kpn I 消化的抗性来检测突变噬菌体。我们的结果表明，HMT 诱变是有针对性的，并且修饰胸腺嘧啶的缺失或颠换是由单加合物或交联引起的主要序列变化。将单加合的 DNA 转染到 Uvr A 缺陷菌株中不会改变突变模式，但会增加各自的突变频率。将交联的 DNA 转染到 SOS 诱导的宿主中会导致出现其他类型的突变，这归因于靶向和非靶向突变的增加。
