Fig. 1.

Schematic outline of the PCR-based screening procedure for transposon insertions. Thick black arrows indicate the IRs of the transposon. colE1, replication origin in E. coli; gent^R, gentamicin-resistance marker encoded by the aacA-aphD gene. The transposase-encoding gene (TnpA) is located outside the transposed region of the pMT85 plasposon. The locations of primers used for the PCR-based screening are shown by thin arrows. The forward and reverse primers are specific to the gene of interest; the MT85.1 and MT85.2 primers are complementary to transposon sequences. Two orientations of the transposed elements are possible, as indicated by (1) and (2).