Ohtsubo E, Zenilman M, Ohtsubo H
Proc Natl Acad Sci U S A. 1980 Feb;77(2):750-4. doi: 10.1073/pnas.77.2.750.
We studied in vivo recombination between the plasmid pHS1, a temperature-sensitive replication mutant carrying tetracycline resistance, and pSM1, a small plasmid carrying one copy of the insertion element IS1. Recombinant plasmids were found by selection for tetracycline resistance at 42 degrees C. Their formation was independent of recA function. Analysis of the physical structures of various recombinant DNA molecules with electron microscopy and restriction endonucleases revealed that pSMI was integrated at its IS1 into numerous sites on pHS1, giving rise to a duplication of IS1 in the same orientation at both junctions. Nucleotide sequence analysis of recombinant plasmids and their parental plasmid DNA revealed that nine nucleotides at a target site were duplicated at the junction of each IS1. This phenomenon implies that plasmids containing a translocatable DNA element can be potential transposons.
我们研究了携带四环素抗性的温度敏感复制突变体质粒pHS1与携带一个插入元件IS1拷贝的小质粒pSM1之间的体内重组。通过在42℃下选择四环素抗性来发现重组质粒。它们的形成与recA功能无关。用电子显微镜和限制性内切酶对各种重组DNA分子的物理结构进行分析，结果表明pSMI在其IS1处整合到pHS1的多个位点上，导致在两个连接处相同方向上IS1重复。对重组质粒及其亲本质粒DNA的核苷酸序列分析表明，每个IS1连接处的靶位点有9个核苷酸发生了重复。这种现象表明，含有可转移DNA元件的质粒可能是潜在的转座子。
