Fig. 9
From: The IS6 family, a clinically important group of insertion sequences including IS26
Two Models for TU formation from the Pseudo-compound Transposon Tn4325B. Symbols are as in the previous figures. The small filled circle within one of the internal IS flanks (white arrow) indicates the additional GG dinucleotide carried by Tn4325B. Both use an intramolecular replicative transposition pathway in a cis configuration. In the top panel, the wildtype IS uses the flank of the mutated IS as a target. This would generate a TU with a single IS and both internal flanking sequences and an excisant with two tandem IS copies separated by a mutant flank. In the lower panel, the TU carries two tandem IS copies and the excisant