Figure 6. Target site sequences and base-pairing interactions for the insertion of retargeted RmInt1 at different positions in the lacZ gene. Retargeted introns are denoted by a number corresponding to the nucleotide position of the intron insertion site in the target gene coding sequence. “s” and “as” indicate the sense and antisense strands, respectively. The arrowhead indicates the intron insertion site. The score obtained with the computer algorithm is indicated, together with the targeting frequency, which was determined by counting blue and white colonies in both the lagging and leading orientations with respect to the replication origin. The values shown are means + standard deviations for three independent determinations. (n.d.) not detectable.