Figure 4.—

Modifications of target-site sequences that are associated with insertion and excision of Idaten and Idaten-2. The 3-bp TSDs are shown in boldface type. Open rectangles with closed triangles at their ends represent Idaten or Idaten-2 inserts. In the revertants, sequences in the middle are the footprints left following transposon excision. Portions of these footprints are antiparallel versions of the sequences to the left of the target site (wavy underlining) or the right side (straight underlining). (A) Mutant InvA4 and its revertants. Dots in two places indicate base changes in the TSD that were present following excision. (B) Mutant InvC2 and its revertants. All three revertants examined had a missing nucleotide in the right half of the TSD (double underline). The dotted line under three bases on the right side (CGC) calls attention to the fact that they are the same as the TSD, providing a possible reason why only this strain underwent a one-base deletion during excision. (C) InvC3 and its revertant. (D) InvC4 and its revertants. (E) InvC5 and its revertants. All revertants studied here were independent isolates.