Method for controlling the gene expression in lactic acid bacteria

摘要

The present invention relates to a method for the controlled expression, in a lactic acid bacterium, of a DNA fragment containing one or more genes coding for a desired characteristic, characterised in that the DNA fragment is under the control of a promoter for a microbial gene which codes for an antimicrobial peptide, and the gene/the genes are brought to expression on the DNA fragment by the addition of a suitable inducing factor for the transcription activation. The promoter is preferably the nisA promoter from Lactococcus lactis. The inducer is preferably acceptable for food products, and more preferentially is nisin or derivatives thereof. The invention also relates to a method for the production of proteins or RNA, as well as to a method for the preparation of dairy products using the expression system according to the invention. The invention finally relates to lactic acid bacteria and expression vectors for use in the method according to the invention.