Figure 2

PCR amplification of IS flanking DNA from E. coli strains CGSC6300, TD2 and TD10. Results for IS1, 2, 3, and 5 and 186 are shown. Genomic DNA was digested with Rsa I, ligated with vectorette units and amplified by vPCR. Each panel shows the PCR products generated by two outward IS-specific primers (arrows) of an IS in combination with the vectorette primer. Flanking DNA fragments from both sides of each IS location were amplified. The PCR products were excised, purified, sequenced and identified from the genome sequence of E. coli strain MG1655 [17]. A PCR fragment flanking a known IS site in MG1655 is indicated by the element's name followed by an identifying numeral; for example, IS1-1 is one of 7 IS1 elements in the MG1655 genome. Additional flanking DNAs not found in MG1655 are labeled with the b# of the gene in which the IS is located. PCR products were separated in 1.4% agarose gels and stained with ethidium bromide. Intense bands in the 100 kb ladder correspond to 500 and 1000 bp.