Open AccessConservation of key elements of natural competence in Lactococcus lactis ssp.
Author(s) -
Wydau Sandra,
Dervyn Rozenn,
Anba Jamila,
Dusko Ehrlich S.,
Maguin Emmanuelle
Publication year - 2006
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 - 10.1111/j.1574-6968.2006.00141.x
Subject(s) - lactococcus lactis , biology , gene , horizontal gene transfer , genetics , bacterial genetics , bacteria , genome , escherichia coli , lactic acid
Natural competence is active in very diverse species of the bacterial kingdom and probably participates in horizontal gene transfer. Recently, the genome sequence of various species, including Lactococcus lactis , revealed the presence of homologues of competence genes in bacteria, which were not previously identified as naturally transformable. We investigated the conservation among lactococcal strains of key components of the natural competence process in streptococci: (i) comX which encodes a sigma factor, allowing the expression of the late competence genes involved in DNA uptake, (ii) its recognition site, the cin‐box and (iii) dprA which encodes a protein shown to determine the fate of incoming DNA. The comX and dprA genes and the cin‐box appeared conserved among strains, although some L. lactis ssp. lactis strains presented an inactivated dprA gene. We established that ComX controls the expression of the late competence genes in L. lactis . In conclusion, our work strongly suggests that ComX has the same role in streptococci and L. lactis , i.e. the regulation of late competence genes. It also allowed the identification of a set of L. lactis strains and the construction of a comX overexpression system, which should facilitate the investigation of the natural competence activity in lactococci.