Rasmussen J L, Odelson D A, Macrina F L
J Bacteriol. 1987 Aug;169(8):3573-80. doi: 10.1128/jb.169.8.3573-3580.1987.
The nucleotide sequence and genetic analyses of one of the directly repeated sequences flanking the macrolide-lincosamide-streptogramin B drug resistance determinant, ermF, from the Bacteroides fragilis R plasmid, pBF4, suggested that this region is an insertion sequence (IS) element. This 1,155-base-pair element contained partially matched (20 of 25 base pairs) terminal-inverted repeats, overlapping, anti-parallel open reading frames, and nine promoterlike sequences, including three that were oriented outward. Analysis of this sequence revealed no significant nucleotide homology to 13 other known IS elements. Inasmuch as Southern blot hybridization analysis detected homologous sequences in chromosomal DNA and its G+C content (42 mol%) was similar to that of B. fragilis, the data suggested that this element is of Bacteroides origin. Transposition promoted by this element was demonstrated in recA E. coli. Recombinants were recovered by selecting for the activation of a promoterless chloramphenicol resistance gene on the plasmid pDH5110 and were characterized by restriction endonuclease mapping and Southern blot hybridization. We propose that this IS element be designated IS4351.
对脆弱拟杆菌R质粒pBF4上大环内酯-林可酰胺-链阳菌素B耐药决定簇ermF侧翼的一个直接重复序列进行核苷酸序列和遗传分析，结果表明该区域是一个插入序列（IS）元件。这个1155个碱基对的元件包含部分匹配（25个碱基对中的20个）的末端反向重复序列、重叠的反平行开放阅读框以及九个启动子样序列，其中三个是向外定向的。对该序列的分析显示，它与其他13个已知的IS元件没有显著的核苷酸同源性。由于Southern印迹杂交分析在染色体DNA中检测到同源序列，并且其G+C含量（42摩尔%）与脆弱拟杆菌的相似，数据表明该元件起源于拟杆菌属。通过该元件促进的转座在recA大肠杆菌中得到证实。通过选择激活质粒pDH5110上无启动子的氯霉素抗性基因来回收重组体，并通过限制性内切酶图谱分析和Southern印迹杂交对其进行表征。我们建议将这个IS元件命名为IS4351。
