FIG. 5.

Stacked ISs. (A) A linear portrayal of a region of plasmid α in the vicinity of its arbitrary origin, a unique SalI site within all7001. Except for alr7007, ORFs asr7385 through alr7009 are annotated as encoding transposases. The ends of the ISs are indicated by individualized brackets. (B) A view of the same region illustrating that IS(all7008, all7009) has, at the position of the vertical arrowhead in Fig. 4E and F, been interrupted by insertion of IS(alr7386′, alr7003′, asr7006, alr7007), itself interrupted by IS(all7002, all7001) and by IS(all7005, all7004). Insertion of the latter two ISs added stop codons that subdivided IS(alr7386′, etc.) into its several “ORFs,” “alr7386,” “alr7003,” and “asr7006.” The horizontal arrowheads represent IRs at the ends of the ISs, and the series of letters next to some of these arrowheads represent DRs flanking the IRs.