title: LnqR, a TetR-family transcriptional regulator, positively regulates lacticin Q production in Lactococcus lactis QU 5.
abstract: Lacticin Q is an unmodified leaderless bacteriocin produced by Lactococcus lactis QU 5. It has been revealed that the production and self-immunity of lacticin Q are facilitated by a gene cluster lnqQBCDEF The gene for a putative TetR-family transcriptional regulator, termed lnqR, was found nearby the lnqQBCDEF cluster, but its involvement in lacticin Q biosynthesis remained unknown. In this study, we created an LnqR-overexpressing QU 5 recombinant by using lactococcal constitutive promoter P32 The recombinant QU 5 showed enhanced production of and self-immunity to lacticin Q. RT-PCR analysis has revealed that an overexpression of LnqR increases the amounts of lnqQBCDEF transcripts, and these six genes are transcribed as an operon in a single transcriptional unit. Interestingly, LnqR expression and thus lacticin Q production by L. lactis QU 5 was found temperature dependent, while LnzR, an LnqR-homologue, in L. lactis QU 14 was expressed in a similar but not identical manner to LnqR, resulting in dissimilar bacteriocin productivities by these strains. This report demonstrates LnqR as the first TetR-family transcriptional regulator involved in LAB bacteriocin biosynthesis and that, as an exceptional case of TetR-family regulators, LnqR positively regulates the transcription of these biosynthetic genes.
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Shun
authors.initials: S
authors.lastname: Iwatani
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Ishibashi
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Institute of Food Science and Technology, University of the Philippines Los Baños College, Laguna 4031, Philippines.
authors.forename: Floirendo P
authors.initials: FP
authors.lastname: Flores
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan zendo@agr.kyushu-u.ac.jp.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Zendo
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Nakayama
authors.affiliation: Department of Bioscience and Biotechnology, Faculty of Agriculture, Graduate School, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan Department of Functional Metabolic Design, Bio-Architecture Center, Kyushu University, 6-10-1 Hakozaki, Higashi-ku, Fukuoka 812-8581, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Sonomoto
mesh_terms: D001430:Bacteriocins / Q000096:biosynthesis*; D015964:Gene Expression Regulation, Bacterial; D005798:Genes, Bacterial; D013294:Lactococcus lactis / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D009876:Operon; D011401:Promoter Regions, Genetic; D060888:Real-Time Polymerase Chain Reaction
chemical_list: D001430:Bacteriocins; C548356:lacticin Q, Lactococcus lactis
keywords: Lactococcus lactis; TetR-family regulator; bacteriocin; lacticin Q