FIG. 3.

PCR amplification of the locus of Tn917 insertion from chromosomal DNA of wild-type (wt) CS101 and Tn917 mutant CS101:ZQ6. The locus containing the Tn917 insertion was amplified either from chromosomal DNA of wild-type CS101 by a conventional PCR protocol or from chromosomal DNA of the mutant CS101:ZQ6 by an XL PCR protocol as described in Materials and Methods. A primer designed specifically for the sagA gene and a second primer specifically complementary to a sequence about 700 bp downstream of the Tn917 insertion site were used to determine if the proposed insertion site of Tn917 was correct. The PCR products were separated in a 1% agarose gel and visualized under UV light, after ethidium bromide staining.