Grindley N D
Cell. 1978 Mar;13(3):419-26. doi: 10.1016/0092-8674(78)90316-1.
Three independent integrations of the E. coli insertion sequence, IS1, into the gal operon have been analyzed. DNA sequences of portions of the wild-type galT gene which act as the target sites for these insertions, as well as the corresponding gal/IS1 junctions, are reported. Two features are particularly noteworthy. First, similar sequences appearing in inverted orientation consitute the ends of IS1: 18 of the terminal 23 base pairs at each end are identical. Second, in all three insertions, a 9 base pair segment found once in the wild-type sequence at the site of insertion is duplicated and appears in the same orientation at each end of the inserted element. The sequence of this 9 base pair repeat is different for each insertion analyzed. No homology between the inverted repeat sequences at the ends of IS1 and the sequences of the target sites is observed. Models for the mechanism of IS1 insertion are proposed.
已对大肠杆菌插入序列IS1插入半乳糖操纵子的三个独立整合进行了分析。报告了作为这些插入靶位点的野生型半乳糖转运酶（galT）基因部分的DNA序列，以及相应的半乳糖/IS1连接点。有两个特征特别值得注意。首先，以反向排列出现的相似序列构成了IS1的末端：两端23个碱基对中的18个是相同的。其次，在所有三次插入中，在野生型序列中插入位点处仅出现一次的一个9碱基对片段被复制，并以相同方向出现在插入元件的两端。对于所分析的每次插入，这个9碱基对重复序列的序列都不同。未观察到IS1末端的反向重复序列与靶位点序列之间存在同源性。提出了IS1插入机制的模型。
