Six putative two-component regulatory systems isolated from Lactococcus lactis subsp. cremoris MG1363.
The genetic elements specifying six putative two-component regulatory systems (2CSs) were identified on the chromosome of Lactococcus lactis MG1363. These 2CSs appear to represent distinct loci, each containing a histidine kinase and response-regulator-encoding gene pair. Transcriptional analysis of the six 2CSs was performed either by generating transcriptional fusions to a reporter gene or by primer extension. Two of the systems appeared to be expressed constitutively at a high level, whilst the remaining four exhibited growth-phase-dependent expression. Insertional mutagenesis established that the two constitutively expressed 2CSs are necessary for normal cell growth and/or survival. Mutational analysis of the remaining four systems revealed that they are implicated in susceptibility to extreme pH, osmotic or oxidative conditions, or the regulation of phosphatase activity in L. lactis.
O'Connell-Motherway
Mary
M
Departments of Microbiology, and Food Science and Technology, and National Food Biotechnology Centre, National University of Ireland, Cork, Ireland1.
van Sinderen
Douwe
D
Departments of Microbiology, and Food Science and Technology, and National Food Biotechnology Centre, National University of Ireland, Cork, Ireland1.
Morel-Deville
Françoise
F
Laboratoire de Recherche sur la Viande2 and Laboratoire de Génétique Microbienne3, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
Fitzgerald
Gerald F
GF
Departments of Microbiology, and Food Science and Technology, and National Food Biotechnology Centre, National University of Ireland, Cork, Ireland1.
Ehrlich
S Dusko
SD
Laboratoire de Recherche sur la Viande2 and Laboratoire de Génétique Microbienne3, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
Morel
Patrice
P
Laboratoire de Recherche sur la Viande2 and Laboratoire de Génétique Microbienne3, Institut National de la Recherche Agronomique, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France.
D000595:Amino Acid Sequence; D001483:Base Sequence; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D013294:Lactococcus lactis / Q000502:physiology*; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D015398:Signal Transduction / Q000235:genetics*