FIG. 1.

(A) Genetic organization of the chromosomal locus containing the gut operon in L. casei strains BL23 and ATCC 334. Hairpin loops indicate putative rho-independent transcriptional terminators. fsa refers to fructose-6-phosphate aldolase. The positions of the DNA probe used in Northern blot experiments and primer gutbc4 used in RT-PCR analysis are indicated. (B) DNA sequence of the gut promoter region and the 5′ end of gutF. The GutR-protected regions (I and II) are shown in shaded boxes. The inverted repeat motif is shown by convergent arrows. The transcriptional start site of the gut operon is indicated by an arrow. The putative ribosome-binding site (RBS) and −10 and −35 promoter sequences are underlined. A cre-like sequence is shown in boldface type.