Kushner I Kh, Ovadis M I, Chernin L S
Genetika. 1980;16(10):1775-85.
The multicopy, conjugative R6K plasmid is responsible for the increase in the number of temperature-resistant (Tr) clones formed by Escherichia coli K-12 E486 strain, carrying a ts mutation dnaE486 in the gene coding for DNA polymerase III. The effect observed is not due to the mutator action of R6K or a mutation in the plasmid and requires the intactness of the host recA function. Tr derivatives MG488 and MG492, isolated under non-permissive condition from the strain E486(R6K), still possess the ts allele dnaE486 in the chromosome. Both Tr derivatives are more resistant to UV-irradiation and the characterized with a different level of spontaneous and UV-induced mutagenesis as compared to the initial strain E486(R6K). The data obtained suggest that the plasmid R6K is involved in the metabolism of chromosomal DNA of the host.
多拷贝接合型R6K质粒导致携带DNA聚合酶III编码基因中ts突变dnaE486的大肠杆菌K-12 E486菌株形成的耐温（Tr）克隆数量增加。观察到的这种效应并非由于R6K的诱变作用或质粒中的突变，而是需要宿主recA功能完整。在非允许条件下从菌株E486(R6K)分离得到的Tr衍生物MG488和MG492，其染色体中仍具有ts等位基因dnaE486。与初始菌株E486(R6K)相比，这两种Tr衍生物对紫外线辐射更具抗性，并且具有不同水平的自发诱变和紫外线诱导诱变特征。所获得的数据表明，质粒R6K参与宿主染色体DNA的代谢。
