Intracellular effectors regulating the activity of the Lactococcus lactis CodY pleiotropic transcription regulator.
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.
Petranovic
Dina
D
Génétique Microbienne, Institut National de la Recherche Agronomique, 78352 Jouy-en-Josas Cedex, France.
Guédon
Eric
E
Sperandio
Brice
B
Delorme
Christine
C
Ehrlich
Dusko
D
Renault
Pierre
P
D000222:Adaptation, Physiological; D000597:Amino Acids, Branched-Chain / Q000378:metabolism*; D001412:Bacillus subtilis / Q000235:genetics / Q000378:metabolism; D001426:Bacterial Proteins / Q000235:genetics / Q000378:metabolism*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D020536:Enzyme Activators / Q000494:pharmacology; D015964:Gene Expression Regulation, Bacterial; D017930:Genes, Reporter; D006160:Guanosine Triphosphate / Q000378:metabolism*; D007532:Isoleucine / Q000378:metabolism; D007763:Lac Operon; D013294:Lactococcus lactis / Q000235:genetics / Q000378:metabolism*; D007930:Leucine / Q000378:metabolism; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D009876:Operon; D011401:Promoter Regions, Genetic; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D014633:Valine / Q000378:metabolism; D001616:beta-Galactosidase / Q000235:genetics / Q000378:metabolism
D000597:Amino Acids, Branched-Chain; D001426:Bacterial Proteins; D004268:DNA-Binding Proteins; D020536:Enzyme Activators; D012097:Repressor Proteins; D007532:Isoleucine; D006160:Guanosine Triphosphate; D008156:Luciferases; D001616:beta-Galactosidase; D007930:Leucine; D014633:Valine