FIG. 1.

Linear DNA transformation substrate. Plasmid pKM131 contains the 2,557-bp PvuII lacZ fragment inserted into the PvuII site of pBR322, with a 1,100-bp kanamycin resistance-conferring fragment inserted into the BclI site within lacZ. When cut with BglI, pKM131 generates a fragment containing the kan gene, flanked by 921 and 1,200 bp of lacZ sequence. A similar plasmid, pKM133 (not shown), contains the tetracycline resistance determinant from pBR322, flanked by 1,256 and 1,301 bp of lacZ sequence.