Sektas Marian, Specht Maciej
Department of Microbiology, University of Gdansk, 80-822 Gdansk, ul.Kladki 24, Poland.
Plasmid. 2005 Mar;53(2):148-63. doi: 10.1016/j.plasmid.2004.04.006. Epub 2004 Dec 2.
The Cre/loxP recombination system of bacteriophage P1 is one of the most powerful tools in genome engineering. We report, however, that the activity of the Cre/loxP system interferes with the stability of the multicopy loxP-bearing plasmids in Escherichia coli recA bacteria. Due to the predominantly unidirectional Cre-mediated high-order multimer formation of these plasmids, the number of their copies (overall yield) gradually decreases. Intermolecular recombination reduces the copy number of plasmids and eventually increases their segregational instability. We have found that in the presence of even the slightest amount of Cre activity, loxP-bearing plasmids continuously undergo multimerization, which very rapidly leads to loxP-plasmid free cells. Our results are compatible with the hypothesis of the multimer catastrophe [Cell, 1984 (36), 1097].
噬菌体P1的Cre/loxP重组系统是基因组工程中最强大的工具之一。然而，我们报告称，Cre/loxP系统的活性会干扰携带loxP的多拷贝质粒在大肠杆菌recA细菌中的稳定性。由于这些质粒主要通过单向的Cre介导形成高阶多聚体，其拷贝数（总产量）会逐渐减少。分子间重组会降低质粒的拷贝数，并最终增加其分离不稳定性。我们发现，即使存在最微量的Cre活性，携带loxP的质粒也会持续发生多聚化，这会非常迅速地导致不含loxP质粒的细胞出现。我们的结果与多聚体灾难假说[《细胞》，1984年（36），1097]相符。
