LnqR, a TetR-family transcriptional regulator, positively regulates lacticin Q production in Lactococcus lactis QU 5

Shun Iwatani, Naoki Ishibashi, Floirendo P. Flores, Takeshi Zendo, Jiro Nakayama, Kenji Sonomoto

Research output: Contribution to journalLetter

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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.

Original languageEnglish
Article numberfnw200
JournalFEMS microbiology letters
Issue number18
Publication statusPublished - Sep 1 2016


All Science Journal Classification (ASJC) codes

  • Microbiology
  • Molecular Biology
  • Genetics

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