FIG. 7.

Model for integration of CTn9343 into the B. fragilis chromosome. (A) Circular intermediate of CTn9343 prior to integration. attCTn9343 in the right-left junction is enlarged to show the IR sequence at the ends of CTn9343 separated by AT. (B) Sequence of the region of hsdS where CTn86 integrates (B. fragilis aattB). The 7-bp target site in hsdS is indicated by the box. The arrow shows the direction of hsdS transcription. Integration of CTn9343 interrupts HsdS in tyrosine (Y) 398. Like CTn86, there is no sequence similarity between the ends of CTn9343 and the target site. (C) Sequences of the ends of CTn9343 and flanking regions. Like CTn86, integration of CTn9343 into the target site resulted in duplication of the target sites (shown in boxes).