Mooibroek H, Arnberg A C, de Jong B, Venema G
Mol Gen Genet. 1985;199(1):82-8. doi: 10.1007/BF00327514.
The physical fate of plasmid DNA after entry into human fibroblasts was studied using Southern hybridisation and electron microscopy. Exposure of the cells (5 X 10(5) per well) to pC194 DNA-CaPi, containing 50 micrograms plasmid DNA, resulted in the occasional formation of interlocked molecules. Exposure to a co-precipitate containing 100 micrograms pC194 plasmid DNA per well resulted in an increase of interlocked molecules by a factor of 10-20 relative to the number of monomers. In addition, new classes of molecules were observed. After prolonged incubation of the cells exposed to the higher DNA concentration, the plasmid DNA was partly contained in structures with a very low electrophoretic mobility. Upon restriction endonuclease digestion of the re-extracted DNA, a pattern of bands was observed, suggesting the involvement of illegitimate recombination between non-random plasmid DNA sequences in the formation of the new classes of molecules.
利用Southern杂交和电子显微镜技术研究了质粒DNA进入人成纤维细胞后的物理命运。将细胞（每孔5×10⁵个）暴露于含有50微克质粒DNA的pC194 DNA - CaPi中，偶尔会形成互锁分子。将细胞暴露于每孔含有100微克pC194质粒DNA的共沉淀物中，互锁分子的数量相对于单体数量增加了10 - 20倍。此外，还观察到了新的分子类型。在将暴露于较高DNA浓度的细胞长时间孵育后，质粒DNA部分包含在电泳迁移率非常低的结构中。对重新提取的DNA进行限制性内切酶消化后，观察到了条带模式，这表明在新分子类型的形成过程中，非随机质粒DNA序列之间发生了异常重组。
