Method for controlling the gene expression in lactic acid bacteria

摘要

The present invention relates to a method of controlledly inducing expression of a DNA fragment in a lactic acid bacterium, the DNA fragment containing one or more genes which code for a desired property, characterized - in that the DNA fragment is under the control of a promoter of a microbial gene which codes for an antimicrobial peptide, and - in that expression of the gene/genes on the DNA fragment is induced by the addition of a suitable inducing factor for the transcription activation. The promoter is preferably the nisA promoter from Lactococcus lactis. The inducing factor is preferably acceptable for food products, more preferably being nisine or derivatives thereof. The invention further relates to a method for the production of proteins or RNA and to a method for preparing dairy products, employing 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.