Maley J, Roberts I S
Department of Microbiology and Immunology, University of Leicester, UK.
FEMS Microbiol Lett. 1994 Oct 15;123(1-2):219-24. doi: 10.1111/j.1574-6968.1994.tb07225.x.
The nucleotide sequence of IS1126, the only insertion sequence so far isolated from the oral pathogen Porphyromonas gingivalis, has been determined. It had a nucleotide sequence of 1338 base pair (bp) flanked by 12 bp perfect inverted repeats and generated a 5 bp target site duplication. The single major open reading frame encoded a predicted protein of 361 amino acids and molecular mass of 41 kDa. The gene encoding the transposase was subcloned into pUC18 and the transposase expressed in Escherichia coli minicells. The predicted amino acid sequence of the transposase had homology to putative transposases of IS1106 and IS1186 both of which belong to the IS5 group within the IS4 super-family of insertion elements. On the basis of this homology we propose that IS1126 should also be included in the IS5 group. Southern-blot analysis of a number of P. gingivalis strains using IS1126 as a probe revealed a unique pattern of hybridisation for each strain and the absence of IS1126 from other closely related Porphyromonas species. This should allow IS1126 to be used as a rapid epidemiological tool in studying oral infections by P. gingivalis.
已确定IS1126的核苷酸序列，它是目前从口腔病原体牙龈卟啉单胞菌中分离出的唯一插入序列。其核苷酸序列为1338个碱基对（bp），两侧是12个bp的完美反向重复序列，并产生了一个5 bp的靶位点重复序列。单一的主要开放阅读框编码一个预测的361个氨基酸的蛋白质，分子量为41 kDa。编码转座酶的基因被亚克隆到pUC18中，并在大肠杆菌小细胞中表达转座酶。转座酶的预测氨基酸序列与IS1106和IS1186的推定转座酶具有同源性，这两者都属于插入元件IS4超家族中的IS5组。基于这种同源性，我们提出IS1126也应归入IS5组。使用IS1126作为探针，对多个牙龈卟啉单胞菌菌株进行Southern杂交分析，结果显示每个菌株都有独特的杂交模式，且其他密切相关的卟啉单胞菌物种中不存在IS1126。这使得IS1126可作为研究牙龈卟啉单胞菌引起的口腔感染的快速流行病学工具。
