Kotova V Iu, Zavil'gel'skiĭ G B, Belogurov A A
Mol Biol (Mosk). 1988 Jan-Feb;22(1):270-6.
The capability of a number of plasmids of incN and incI groups to alleviate an action of type I EcoK, EcoB, EcoD, and EcoA restriction endonucleases on the unmodified DNA was revealed. The efficiency of EcoK action on lambda 0 DNA is alleviated about 10 divided by 100 fold in E. coli K12 AB 1157 bacteria containing the plasmid of incN group (pKM101, N3, pJA4733) or incI group (R144, R648; R621a; ColIb-P9). We have cloned ard gene of ColIb-P9 plasmid (SalI-C fragment) in pBR322 multicopying vector. A hybrid clone abolishing the EcoK restriction has been received. Ard gene activity is independent of the recA, recBc, recF, lexA, umuC, lon bacterial genes activity. Ard gene's product does not inhibit the EcoK restriction endonuclease action as well as ocr protein (phage T7) and does not increase the process of methylation of DNA as well as ral protein of phage lambda.
已发现一些IncN和IncI组质粒能够减轻I型EcoK、EcoB、EcoD和EcoA限制性核酸内切酶对未修饰DNA的作用。在含有IncN组质粒（pKM101、N3、pJA4733）或IncI组质粒（R144、R648；R621a；ColIb-P9）的大肠杆菌K12 AB 1157细菌中，EcoK对λ0 DNA的作用效率降低了约10至100倍。我们已将ColIb-P9质粒的ard基因（SalI-C片段）克隆到pBR322多拷贝载体中。获得了一个消除EcoK限制的杂交克隆。Ard基因的活性不依赖于recA、recBc、recF、lexA、umuC、lon细菌基因的活性。Ard基因的产物既不抑制EcoK限制性核酸内切酶的作用，也不抑制ocr蛋白（噬菌体T7），并且既不增加DNA的甲基化过程，也不增加噬菌体λ的ral蛋白。
