Martin R R, Thorlton C L, Unger L
J Bacteriol. 1981 Feb;145(2):713-21. doi: 10.1128/jb.145.2.713-721.1981.
Hfr strains of Escherichia coli were obtained by integrative suppression of a dnaA(Ts) mutation by the Inc P-1 plasmid RP1 without prior creation of an unnatural homology between the plasmid and the E. coli chromosome. Unmodified RP1 mobilized the polarized transfer of the chromosome in a counterclock-wise direction from a distinct origin between 81 min (pyrE) and 82 min (dnaA) with pyrE as a leading marker. Inheritance of RP1-Hfr chromosomal and antibiotic resistance genes was due to recombination with the recipient chromosome, as shown by the need for a functional recA system. The acquisition of temperature resistance and donor ability was accompanied by the disappearance of free plasmid when the selection pressure for integration was maintained (growth at 41 degrees C); the loss of temperature resistance and donor ability was accompanied by the reappearance of autonomous RP1 when the selection pressure was removed (growth at 30 degrees C).
通过Inc P-1质粒RP1对dnaA（Ts）突变进行整合抑制，在未事先在质粒与大肠杆菌染色体之间建立非自然同源性的情况下，获得了大肠杆菌的高频重组（Hfr）菌株。未修饰的RP1从81分钟（pyrE）和82分钟（dnaA）之间的一个独特起点以逆时针方向动员染色体的极性转移，其中pyrE作为领先标记。RP1-Hfr染色体和抗生素抗性基因的遗传是由于与受体染色体的重组，功能性recA系统的需求证明了这一点。当维持整合的选择压力（在41摄氏度下生长）时，获得温度抗性和供体能力伴随着游离质粒的消失；当去除选择压力（在30摄氏度下生长）时，温度抗性和供体能力的丧失伴随着自主RP1的重新出现。
