Identification, characterization, and expression of a second, bicistronic, operon involved in the production of lactocin S in Lactobacillus sakei L45.
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| Abstract |
Through the analysis of spontaneous insertion mutants of Lactobacillus sakei L45, a second operon involved in lactocin S production was identified and characterized. The new, bicistronic unit, termed lasXY, is situated immediately upstream of the previously characterized nine-open reading frame (ORF) lactocin S operon (lasA-W) and is transcribed in the opposite direction. The proximal of the two newly identified genes, lasX, specifies a 285-residue protein that is similar to a group of proteins with reported gene regulation functions in gram-positive bacteria. It was demonstrated that the lasX mutants have a strongly reduced level of lasA and lasA-W mRNA, thus indicating the likely cause of the Bac(-) phenotype of these mutants. The second ORF in the operon, lasY, specifies a 300-residue ABC transporter homolog, the function of which is currently obscure. Transcription initiation mapping of the lasXY operon demonstrates that the two lactocin S promoters overlap such that both transcripts initiate within the -35 region of the oppositely oriented promoter. This organization of promoters is unique among this group of regulons and may constitute a modulatory site in the proposed LasX-dependent expression of lasA and downstream genes.
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| Authors | Morten Skaugen, Elizabeth L Andersen, Vigdis H Christie, Ingolf F Nes |
| Journal | Applied and environmental microbiology (Appl Environ Microbiol) Vol. 68 Issue 2 Pg. 720-7 (Feb 2002) ISSN: 0099-2240 [Print] United States |
| PMID | 11823212 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't) |
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