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Intracellular effectors regulating the activity of the Lactococcus lactis CodY pleiotropic transcription regulator
Author(s) -
Petranovic Dina,
Guédon Eric,
Sperandio Brice,
Delorme Christine,
Ehrlich Dusko,
Renault Pierre
Publication year - 2004
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2004.04136.x
Subject(s) - biology , lactococcus lactis , regulator , effector , intracellular , transcription (linguistics) , microbiology and biotechnology , transcription factor , genetics , bacteria , gene , lactic acid , linguistics , philosophy
Summary CodY is a pleiotropic transcriptional regulator conserved in low‐G+C Gram‐positive bacteria. Two distinct signals have been shown independently to influence the activity of this regulator: the level of intracellular GTP in Bacillus subtilis and the level of intracellular branched‐chain amino acids (BCAA) isoleucine, leucine and valine in Lactococcus lactis. Measurement of BCAA and GTP levels in several environmental conditions showed that L. lactis CodY responded to the intracellular BCAA concentrations but not to physiological fluctuations in intracellular GTP. In addition, we demonstrated that CodY from L. lactis did not respond to intracellular GTP even when complementing CodY activity in B. subtilis . However, L. lactis CodY activity could still be modulated in B. subtilis by adding a rich nitrogen source to the growth media. This finding suggests that only BCAA are sensed by L. lactis CodY, whereas both GTP and BCAA signals may be integrated by B. subtilis CodY. The difference in the function of CodY from B. subtilis and L. lactis seems to reflect the difference in the physiology of these two bacteria.