Danilevich V N, Kostiuchenko D A, Negriĭ N V
Mol Biol (Mosk). 1985 Jul-Aug;19(4):1042-52.
A pRP19.6 plasmid is the derivative of the temperature sensitive RPlts12 plasmid and contains a duplicated IS21 (IS8) element. Using temperature sensitive pRP19.6 replication, Hfr strains have been obtained by integration of the plasmid into the chromosome of E. coli rec+ and recA- cells and their properties were studied. According to the results obtained, pRP19.6 insertion into the genome of the rec+ bacteria IS reversible, and its integration into the chromosome of the recA- bacteria produced the stable Hfr strains. To elucidate the mechanism of pRP19.6 excision from the bacterial chromosome, plasmids of R+ transconjugates generated with a low frequency in the crosses between the stable Hfr strains and the rec+ recipients were analyzed. It was shown that the stable Hfr clones might produce stable R1 plasmids as well as a family of deletion KmsTra- derivatives of the pRP19.6. The structure of the KmsTra- was investigated and the mechanism of their formation was proposed. In the light of the data obtained, prospects of pRP19.6 practical application are discussed.
pRP19.6质粒是温度敏感型RPlts12质粒的衍生物，含有一个重复的IS21（IS8）元件。利用温度敏感型pRP19.6复制，通过将该质粒整合到大肠杆菌rec +和recA-细胞的染色体中获得了高频重组（Hfr）菌株，并对其特性进行了研究。根据所得结果，pRP19.6插入rec +细菌基因组是可逆的，而将其整合到recA-细菌的染色体中则产生了稳定的Hfr菌株。为了阐明pRP19.6从细菌染色体上切除的机制，分析了在稳定的Hfr菌株与rec +受体之间的杂交中低频产生的R +转接合子的质粒。结果表明，稳定的Hfr克隆可能产生稳定的R1质粒以及pRP19.6的一系列缺失KmsTra-衍生物。研究了KmsTra-的结构并提出了其形成机制。根据所得数据，讨论了pRP19.6实际应用的前景。
