title: Transcription analysis of a lantibiotic gene cluster from Bifidobacterium longum DJO10A.
abstract: Bifidobacterium longum DJO10A was previously demonstrated to produce a lantibiotic, but only during growth on agar media. To evaluate the feasibility of production of this lantibiotic in broth media, a transcription analysis of the lanA gene was undertaken. Comparative microarray analysis of broth and agar cultures of B. longum DJO10A revealed that the lantibiotic production, modification, transport/peptidase, and immunity genes were significantly upregulated in agar cultures, while the two-component regulatory genes were expressed equally under both conditions. This suggested that the signal transduction regulatory system should function in broth cultures. Real-time PCR and Northern hybridization confirmed that lanA gene expression was significantly repressed in broth cultures. A crude lantibiotic preparation from an agar-grown culture was obtained, and its antimicrobial spectrum analysis revealed a broad inhibition range. Addition of this extract to broth cultures of B. longum DJO10A induced lanA gene expression in a dose-dependent fashion. Subinoculation using >10% of an induced broth culture maintained lanA expression. The expression of lanA was log-phase specific, being significantly downregulated in stationary phase. Transcription start analysis of lanA revealed a 284-bp 5' untranslated region, which was proposed to be involved in repression of transcription, while an inverted repeat structure located at bp -75 relative to the transcription start was strategically located to likely function as a binding site for the two-component response regulator. Understanding the transcription regulation of this lanA gene is the first step toward enabling production of this novel and potentially interesting lantibiotic in broth cultures.
authors: Department of Food Science and Nutrition, Microbial and Plant Genomics Institute, University of Minnesota, 1500 Gortner Ave., St. Paul, MN 55108, USA.
authors: Ju-Hoon
authors: JH
authors: Lee
authors: Xiulan
authors: X
authors: Li
authors: Daniel J
authors: DJ
authors: O'Sullivan
mesh_terms: D001426:Bacterial Proteins / Q000096:biosynthesis; D001430:Bacteriocins / Q000096:biosynthesis* / Q000235:genetics; D001644:Bifidobacterium / Q000235:genetics*; D053898:Biosynthetic Pathways / Q000235:genetics*; D015152:Blotting, Northern; D020869:Gene Expression Profiling; D015964:Gene Expression Regulation, Bacterial; D046228:Microarray Analysis; D005810:Multigene Family; D060888:Real-Time Polymerase Chain Reaction; D024363:Transcription Initiation Site; D014158:Transcription, Genetic
chemical_list: D001426:Bacterial Proteins; D001430:Bacteriocins