Sengstag C, Arber W
Mol Gen Genet. 1987 Feb;206(2):344-51. doi: 10.1007/BF00333593.
A 1.75 kb DNA segment of the bacteriophage P1 genome is known to serve as a preferred target for IS2 insertions. The presence of this fragment in a plasmid expressing the galK gene dramatically increases the proportion of IS2 insertions among spontaneous galK- mutants. Subfragments from two different parts of the 1.75 kb segment independently stimulate IS2 insertion, while another subfragment does not. In the plasmids studied IS2 elements not only insert into the cloned P1 fragment but also into parts of the galK gene with similar probability and mostly in one orientation. Many insertion sites are unique but several specific sites within the preferred target are repeatedly used for IS2 integration. The experimental data are compatible with a proposed cooperative mechanism, according to which more than one attracting sequence on the same plasmid might significantly enhance the probability of a particular target region to attract IS2.
已知噬菌体P1基因组的一段1.75 kb DNA片段是IS2插入的首选靶点。在表达galK基因的质粒中存在该片段会显著增加自发galK -突变体中IS2插入的比例。来自1.75 kb片段两个不同部分的亚片段可独立刺激IS2插入，而另一个亚片段则不能。在所研究的质粒中，IS2元件不仅插入到克隆的P1片段中，而且以相似的概率插入到galK基因的部分区域，且大多为一个方向。许多插入位点是独特的，但首选靶点内的几个特定位点会被反复用于IS2整合。实验数据与提出的协同机制相符，根据该机制，同一质粒上的多个吸引序列可能会显著提高特定靶区域吸引IS2的概率。
