Buvinger W E, Lampel K A, Bojanowski R J, Riley M
J Bacteriol. 1984 Aug;159(2):618-23. doi: 10.1128/jb.159.2.618-623.1984.
A segment of Escherichia coli DNA that contained a discontinuity of homology with Salmonella typhimurium DNA was isolated. The segment, 1,430 base pairs long, was derived from one end of the lac "loop," a region of about 12 kilobase pairs of E. coli DNA, including the lac operon which has no detectable homology with S. typhimurium DNA (K. Lampel and M. Riley, Mol. Gen. Genet. 186:82-86, 1982). The nucleotide sequence of the 1,430-base-pair segment of DNA was determined. The location of the junction of discontinuity of homology within the segment was established by hybridization experiments. Nucleotide sequences at or near the junction were determined to be similar to sequences that are involved in site-specific inversion in S. typhimurium, E. coli, phage P1, and phage Mu. Similar sequences are also present within the terminal inverted repeat sequences of transposon Tn5 and at the V-D-J joining sequences of eucaryotic immunoglobulin genes. Therefore, the lac operon, together with flanking DNA, may have been inserted into the E. coli chromosome at one time via a site-specific recombination event. Rearrangement events of this kind undoubtedly have played a significant role in the evolutionary divergence of chromosomal DNAs.
分离出一段大肠杆菌DNA，该DNA与鼠伤寒沙门氏菌DNA存在同源性间断。这段1430个碱基对长的片段来自lac“环”的一端，lac“环”是大肠杆菌DNA中一段约12千碱基对的区域，包括与鼠伤寒沙门氏菌DNA无明显同源性的lac操纵子（K. 兰佩尔和M. 赖利，《分子与普通遗传学》186:82 - 86, 1982）。测定了该1430个碱基对的DNA片段的核苷酸序列。通过杂交实验确定了该片段内同源性间断连接处的位置。确定连接处或其附近的核苷酸序列与鼠伤寒沙门氏菌、大肠杆菌、噬菌体P1和噬菌体Mu中参与位点特异性倒位的序列相似。转座子Tn5的末端反向重复序列内以及真核免疫球蛋白基因的V - D - J连接序列中也存在类似序列。因此，lac操纵子及其侧翼DNA可能曾通过一次位点特异性重组事件插入到大肠杆菌染色体中。这类重排事件无疑在染色体DNA的进化分歧中发挥了重要作用。
