Jenab S, Johnson E M
Brookdale Center for Molecular Biology, Mount Sinai School of Medicine, New York, NY 10029.
Biochem Biophys Res Commun. 1989 Apr 14;160(1):53-9. doi: 10.1016/0006-291x(89)91619-7.
When monkey COS7 cells are transfected with plasmids pSVod or pSV2-neo, a DNA structure can be detected consisting of two circular forms linked by a duplex bridge. Generation of this structure is enhanced by camptothecin, an inhibitor of DNA topoisomerase I. Generation of dual-circles in vitro, using a DNA replication system with added T-antigen, requires template DNA with an SV40 origin. Heterogeneous dual-circles can be visualized involving two initially independent molecules of different size. Implications for in vitro studies of certain types of recombination are discussed.
当用质粒pSVod或pSV2-neo转染猴COS7细胞时，可检测到一种由双链桥连接的两个环状形式组成的DNA结构。喜树碱（一种DNA拓扑异构酶I抑制剂）可增强这种结构的产生。在添加T抗原的DNA复制系统中进行体外双环生成，需要具有SV40起源的模板DNA。可以观察到涉及两个不同大小的初始独立分子的异质双环。文中讨论了对某些类型重组的体外研究的意义。
