FIG. 1.

Homologous recombination at the MG_312 gene. (A) Schematic representation of a double-crossover recombination between pΔmg312 and the MG_312 gene and gene replacement by the tetM438 selectable marker. Hatched boxes represent flanking regions of the MG_312 gene in suicide plasmid pΔmg312. Black, tetM438 selectable marker. Sizes of fragments resulting from the HindIII (H) digestion of DNAs from the WT strain and several pΔmg312 transformants are also indicated. (B) Southern blot hybridization profiles of genomic DNA from the WT strain and pΔmg312 transformants using the MG_312 flanking regions as a probe.