Open AccessTranscriptional analysis of the cyclopropane fatty acid synthase gene of Lactococcus lactis MG1363 at low pH
Author(s) -
BudinVerneuil Aurélie,
Maguin Emmanuelle,
Auffray Yanick,
Ehrlich S. Dusko,
Pichereau Vianney
Publication year - 2005
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1016/j.femsle.2005.07.007
Subject(s) - lactococcus lactis , biology , microbiology and biotechnology , biochemistry , mutant , escherichia coli , gene , atp synthase , northern blot , plasmid , gene expression , fatty acid , bacteria , genetics , lactic acid
Cyclopropane fatty acid synthase (cfa) catalyses the transfer of a methyl group from S ‐adenosylmethionine (SAM) to unsaturated fatty acids. Northern blot experiments demonstrated that the Lactococcus lactis MG1363 cfa gene is mainly expressed as a bicistronic transcript together with metK , the gene encoding SAM synthetase, and is highly induced by acidity. The cfa promoter was characterized by 5′‐RACE PCR, and fused to β‐galactosidase by cloning into the pAK80 plasmid. This transcriptional fusion was highly induced by acidity (23‐fold at pH 5) as well as during entry into the stationary phase (8‐fold) in L. lactis . Interestingly, the cfa promoter expression is repressed in a L. lactis rel A* mutant which accumulates (p)ppGpp, whereas its induction by acidity appeared independent of (p)ppGpp in L. lactis and in Escherichia coli .