Figure 3. Chromosomal organization of the transcriptional fusion between the yrpAB operon and the lacZY genes in the ∆yrpB strain. Arrows indicate the direction of the transcription and white areas represent the internal fragment of the yrpB used to carry out the insertional mutagenesis of this gene. yrpB′, truncated yrpB gene; cat, chloramphenicol acetyltransferase gene (promoterless); lacZY, genes for lactose fermentation (promoterless); bla, ampicillin resistance gene; P, putative promoter. The black dot represents the origin of replication of the pJP5603 plasmid.