FIG. 1.

Strategy for construction of a suicide plasmid carrying a cat gene cassette placed between the ssuMB and ssuRA genes of the SsuDAT1I system. (A) Construction of pMBcatRA′. Lines between the closed arrowheads are PCR fragments amplified from the above regions. The amplified fragments were fused and cloned into pSET4s. (B) Generation of a mutant RM gene containing the cat gene cassette by allelic exchange via double crossover on the chromosome. (C) Construction of pMABcatRAB. The line between the closed arrowheads is a PCR fragment amplified from the genomic DNA of S. suis 227catIN. The amplified fragment was cloned into pSET4s.