Nilsson B, Uhlén M, Josephson S, Gatenbeck S, Philipson L
Nucleic Acids Res. 1983 Nov 25;11(22):8019-30. doi: 10.1093/nar/11.22.8019.
An Escherichia coli plasmid vector, pUN121, has been constructed which allows for positive selection of transformants harboring DNA inserts. The positive selection of transformants harboring DNA inserts. The vector is based on plasmid pTR262 (Roberts et al. Gene, 12, (1980), 123-127) in which the tetracycline resistance gene is under transcriptional control of the repressor protein coded by the phage lambda cI gene. This plasmid has been rearranged, using in vitro recombinant techniques including oligonucleotide mediated mutagenesis to yield a smaller plasmid (4.4 kb) with unique cloning sites for EcoRI, XmaI and SmaI in addition to the unique HindIII and BclI sites. The plasmid has a functional ampicillin resistance gene and the new restriction sites (EcoRI, XmaI and SmaI) when used for cloning, give rise to tetracycline resistant transformants.
构建了一种大肠杆菌质粒载体pUN121，它可对携带DNA插入片段的转化体进行阳性筛选。携带DNA插入片段的转化体的阳性筛选。该载体基于质粒pTR262（罗伯茨等人，《基因》，第12卷，（1980年），123 - 127页），其中四环素抗性基因受噬菌体λ cI基因编码的阻遏蛋白的转录控制。利用包括寡核苷酸介导的诱变在内的体外重组技术对该质粒进行了重排，以产生一个较小的质粒（4.4 kb），除了独特的HindIII和BclI位点外，还具有EcoRI、XmaI和SmaI的独特克隆位点。该质粒具有功能性氨苄青霉素抗性基因，当用于克隆时，新的限制酶切位点（EcoRI、XmaI和SmaI）会产生四环素抗性转化体。
