Nisen P, Shapiro L
Nature. 1979;282(5741):872-4. doi: 10.1038/282872a0.
The insertion sequence (IS) elements, IS1 and IS2, present in multiple copies in the Escherichia coli chromosome, are transposable genetic elements of known nucleotide sequence. These elements can modulate gene expression, but it is not known whether they normally function in genetic control. To determine whether IS elements could exert control through specific RNA transcripts, we hybridised lambda NNC1857 r14 (carrying IS1) and pBR322 (carrying a portion of IS2) to Northern blots of E. coli RNA. Regions of homology between the IS elements and ribosomal RNA were observed. Computer analysis of reported nucleotide sequences detected large segments of homology between the IS elements and both 23S and 16S rRNA. Additional homologous sequences in phi X174 and a leader region of a ribosomal protein gene cluster were also detected. The homologous sequence between IS2 and 16S rTNA is the same sequence in phi X174 DNA which codes for the ends of the E and D gene and the start of J. The partial IS sequences may represent silent evolutionary remnants or they could modulate the expression of genes carrying these sequences.
插入序列（IS）元件IS1和IS2在大肠杆菌染色体中以多拷贝形式存在，是已知核苷酸序列的可转座遗传元件。这些元件可调节基因表达，但它们是否正常发挥遗传控制功能尚不清楚。为了确定IS元件是否能通过特定的RNA转录本发挥控制作用，我们将λNNC1857 r14（携带IS1）和pBR322（携带IS2的一部分）与大肠杆菌RNA的Northern印迹杂交。观察到IS元件与核糖体RNA之间的同源区域。对已报道核苷酸序列的计算机分析检测到IS元件与23S和16S rRNA之间有大片段同源性。还在φX174和核糖体蛋白基因簇的一个前导区域中检测到了额外的同源序列。IS2与16S rRNA之间的同源序列与φX174 DNA中编码E和D基因末端以及J基因起始的序列相同。部分IS序列可能代表沉默的进化残余物，或者它们可能调节携带这些序列的基因的表达。
