Regulation of lantibiotic lacticin 481 production at the transcriptional level by acid pH

The lantibiotic lacticin 481 operon (lctAMTFEG) is mainly transcribed from P1 and P3, two promoters lying upstream of lctA. A weak additional promoter allows independent expression of the immunity genes (IctFEG). Lacticin 481 production by Lactococcus lactis is stimulated by the acidification due to lactic acid production, and by artificially lowering the pH of the medium. This regulation occurs at the transcriptional level, since P1 and P3 are both acid-induced. P1 is weaker but more tightly regulated than P3. As no specific regulator is encoded by the lacticin 481 operon, P1 and P3 are likely controlled by a general regulator. (C) 2004 Federation of European Microbiological Societies. Published by Elsevier B.V. All rights reserved.