FIG. 3.

Replacement of the fxuA gene in M. smegmatis mc²155 mutant strain M24. (A) Strategy used to replace the fxuA gene by double crossover. The horizontal arrows indicate annealing sites of primers used to confirm the replacement (U3-K1, U9-K2) by using the chromosomal DNA of mutant strain U3 as the template and to generate control fragments by using plasmid pGS22 as the template. The expected sizes of the fragments are indicated between the arrows. (B) Confirmation of replacement of the fxuA gene by PCR analysis of DNA from the U3 ΔfxuA mutant.