Figure 4

RT-PCR analysis of chromosomal and cloned island 4305 gene expression in S. typhimurium. RT-PCR analysis of island 4305 and adjacent genes in S. typhimurium strains χ3339 and χ3339 Δ island 4305 (R995 + island 4305) is depicted. The strain χ3339 Δ island 4305 (R995) was used as a control for the latter strain. The bands shown are from agarose DNA gels that have been stained with ethidium bromide and exposed to UV light. The (+) and (-) lanes represent reactions with and without reverse transcriptase, respectively. The (D) lane represents either χ3339 chromosomal DNA or appropriate plasmid DNA as indicated. The trfA and korB genes are on the R995 vector plasmid. The intergenic region is a region predicted to be non-transcribed that is located between the STM4304 and 4305 genes.