Coppoolse Eric R, de Vroomen Marianne J, van Gennip Femke, Hersmus Bart J M, van Haaren Mark J J
Department of Genetics, Faculty of Earth and Life Sciences, Institute for Molecular Cell Biology, Experimental, Vrije Universiteit, De Boelelaan 1087, 1081, HV Amsterdam, The Netherlands.
Plant Mol Biol. 2005 Jul;58(5):687-98. doi: 10.1007/s11103-005-7705-7.
Cre/lox recombination in vivo has become an important tool to induce chromosomal rearrangements like deletions. Using a combination of Ds transposition and Cre/lox recombination in two independent experiments on chromosomes 6 and 7 of tomato, two sets of somatic deletions up to a size of 200 kb were obtained. The efficiency of somatic deletion decreased with increasing deletion size. The largest germinally transmitted deletion had a size of only 55 kb. The results show that Cre-mediated deletion in somatic cells is less efficient when the lox sites are separated over larger distances. A further drop of the deletion efficiency after germinal transmission of the larger deletions can be explained by the probable loss of genes that are of vital importance to gametophyte function. Plasmid rescue of an 8.4 kb circularised deleted DNA showed that the Cre-mediated deletion takes place in tomato as expected. Since the circular Cre-deleted DNA could only be PCR amplified in plant cells where the deletion was not complete, the double-stranded DNA circle is assumed to be instable.
体内 Cre/lox 重组已成为诱导染色体重排（如缺失）的重要工具。在番茄的 6 号和 7 号染色体上进行的两个独立实验中，结合使用 Ds 转座和 Cre/lox 重组，获得了两组大小达 200 kb 的体细胞缺失。体细胞缺失的效率随着缺失大小的增加而降低。最大的可通过生殖传递的缺失仅为 55 kb。结果表明，当 lox 位点相隔较远时，Cre 介导的体细胞缺失效率较低。较大缺失通过生殖传递后缺失效率的进一步下降，可能是由于对配子体功能至关重要的基因丢失所致。对一个 8.4 kb 环化的缺失 DNA 进行质粒拯救表明，Cre 介导的缺失在番茄中如预期那样发生。由于环状 Cre 缺失 DNA 仅在缺失不完全的植物细胞中能通过 PCR 扩增，因此假定双链 DNA 环不稳定。
