FIG. 4.

orf2 disruption by double crossover via homologous recombination (A) and PCR (left) and Southern blot (right) analyses of the orf2 disruptant (B). The orf2 gene was disrupted by inserting the hygromycin resistance gene (open arrow, Hyg^r) from pReg-dis (see Materials and Methods). The small arrows indicate the primers, dis F and dis R, used for PCR analysis. A part of the hygromycin resistance gene was used as a probe for Southern blot analysis (the double-headed arrow under Hyg^r). W, wild-type strain; D, ctnA disruptant.