Fil'kova S L, Il'ina T S, Gintsburg A L, Ianishevskiĭ N V, Smirnov G B
Genetika. 1988 May;24(5):821-8.
The clones with 4 to 30-fold increased level of tetracycline resistance (TcR) were selected from the strain of Escherichia coli K-12 carrying the pCO107 plasmid. The plasmid is the cointegrate formed from the plasmids pOX38 (F-derivative) and pCT105 (pBR322-derivative carrying the vct operon of Vibrio cholerae eltor and the RSI sequence). pCO107 contains RSI at the junctions of two plasmid genomes. Using restriction analysis and Southern blot hybridization technique it was shown that increased tetracycline resistance is accompanied by amplification of the pCT105 segment of pCO107 and depends upon the presence of direct repeats of flanking RSI. Amplification of the pCT105 also resulted in increased production of the cholerae toxin (CT).
从携带pCO107质粒的大肠杆菌K-12菌株中筛选出对四环素抗性（TcR）水平提高4至30倍的克隆。该质粒是由质粒pOX38（F衍生物）和pCT105（携带霍乱弧菌埃尔托型vct操纵子和RSI序列的pBR322衍生物）形成的共整合体。pCO107在两个质粒基因组的连接处含有RSI。使用限制性分析和Southern印迹杂交技术表明，四环素抗性增加伴随着pCO107的pCT105片段的扩增，并且取决于侧翼RSI的直接重复序列的存在。pCT105的扩增还导致霍乱毒素（CT）产量增加。
