Fig. 8. Analysis of junctions of other IS elements. (A) The promoter–probe vector pCB267. Junctions were constructed using synthetic oligonucleotides which were cloned into this plasmid upstream of a promoterless β-galactosidase gene (lacZ). The plasmid also carries a promoterless phoA gene which was not used in these studies. (B) Junctions of different ISs used. Boundaries of IRR and IRL are shown as brackets and putative –35 or –10 boxes are boxed in grey when close to the canonical hexamers. Five families were represented (IS3, IS1, IS21, IS30, IS110) and nine different junctions including IS911 were cloned in front of the lacZ gene. The promoter used as reference in these experiments was placUV5.