FIG. 2.

Genetic organization of the apf locus in L. gasseri 4B2. The nucleotide sequences of the apf1 and apf2 promoter regions are shown at the top. Putative RNA polymerase binding sites are underlined. Transcriptional start sites are shown in bold type and indicated by vertical arrows. Putative ribosomal binding sites (RBS) are underlined. Primers and their directions are represented by horizontal arrows. PCR amplicons are presented at the bottom, and cloning sites are indicated. The cloning strategy is outlined on the right. k.o., knockout; o.p., overproduction; d.r., down regulation.