Itoh Y, Scott B
Department of Biology, Faculty of Science, Shinshu University, Matsumoto 390, Japan.
Curr Genet. 1997 Aug;32(2):147-51. doi: 10.1007/s002940050259.
As part of a study to investigate the pathways of plasmid pAN7-1 integration in Penicillium paxilli, a molecular analysis of 90 different integration events was carried out. Twenty out of forty five integration events analyzed from transformants obtained without the addition of restriction enzyme to the transformation reaction mixture were single-copy integrations, whereas the remaining 25 were tandem-repeat integrations. The addition of restriction enzyme resulted in a shift in this ratio in favour of single-copy integration events. Analysis of the 33 tandem-repeat integration events showed that the orientation of the plasmid copies was not random, with 88% organized as tandem head-to-tail arrays. De-phosphorylation of linearized pAN7-1 did not affect the frequency with which multiple copies were integrated. This suggests that the predominant mechanism for the generation of tandem repeats in P. paxilli is by homologous recombination rather than in vivo ligation of linearized plasmids.
作为一项研究青霉中质粒pAN7 - 1整合途径的一部分，对90个不同的整合事件进行了分子分析。在转化反应混合物中不添加限制酶获得的转化子所分析的45个整合事件中，有20个是单拷贝整合，而其余25个是串联重复整合。添加限制酶导致该比例向有利于单拷贝整合事件的方向转变。对33个串联重复整合事件的分析表明，质粒拷贝的方向并非随机，88%的质粒以头对头串联排列。线性化的pAN7 - 1去磷酸化并不影响多拷贝整合的频率。这表明在青霉中产生串联重复的主要机制是通过同源重组，而不是线性化质粒的体内连接。
